--- a/browser/app/profile/firefox.js
+++ b/browser/app/profile/firefox.js
@@ -719,19 +719,16 @@ pref("plugins.favorfallback.rules", "nos
 pref("browser.preferences.instantApply", false);
 #else
 pref("browser.preferences.instantApply", true);
 #endif
 
 // Toggling Search bar on and off in about:preferences
 pref("browser.preferences.search", true);
 
-// Use the new in-content about:preferences in Nightly only for now
-pref("browser.preferences.useOldOrganization", false);
-
 // Once the Storage Management is completed.
 // (The Storage Management-related prefs are browser.storageManager.* )
 // The Offline(Appcache) Group section in about:preferences will be hidden.
 // And the task to clear appcache will be done by Storage Management.
 #if defined(NIGHTLY_BUILD)
 pref("browser.preferences.offlineGroup.enabled", false);
 #else
 pref("browser.preferences.offlineGroup.enabled", true);

--- a/browser/base/content/browser-data-submission-info-bar.js
+++ b/browser/base/content/browser-data-submission-info-bar.js
@@ -58,23 +58,17 @@ var gDataNotificationInfoBar = {
     this._actionTaken = false;
 
     let buttons = [{
       label: gNavigatorBundle.getString("dataReportingNotification.button.label"),
       accessKey: gNavigatorBundle.getString("dataReportingNotification.button.accessKey"),
       popup: null,
       callback: () => {
         this._actionTaken = true;
-        // The advanced subpanes are only supported in the old organization, which will
-        // be removed by bug 1349689.
-        if (Services.prefs.getBoolPref("browser.preferences.useOldOrganization")) {
-          window.openAdvancedPreferences("dataChoicesTab", {origin: "dataReporting"});
-        } else {
-          window.openPreferences("privacy-reports", {origin: "dataReporting"});
-        }
+        window.openPreferences("privacy-reports", {origin: "dataReporting"});
       },
     }];
 
     this._log.info("Creating data reporting policy notification.");
     this._notificationBox.appendNotification(
       message,
       this._DATA_REPORTING_NOTIFICATION,
       null,

--- a/browser/base/content/browser-media.js
+++ b/browser/base/content/browser-media.js
@@ -164,21 +164,17 @@ var gEMEHandler = {
     } else {
       document.getElementById(anchorId).removeAttribute("firstplay");
     }
 
     let mainAction = {
       label: gNavigatorBundle.getString(btnLabelId),
       accessKey: gNavigatorBundle.getString(btnAccessKeyId),
       callback() {
-        if (Services.prefs.getBoolPref("browser.preferences.useOldOrganization")) {
-          openPreferences("paneContent", {origin: "browserMedia"});
-        } else {
-          openPreferences("general-drm", {origin: "browserMedia"});
-        }
+        openPreferences("general-drm", {origin: "browserMedia"});
       },
       dismiss: true
     };
     let options = {
       dismissed: true,
       eventCallback: aTopic => aTopic == "swapping",
       learnMoreURL: Services.urlFormatter.formatURLPref("app.support.baseURL") + "drm-content",
     };

--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -543,21 +543,17 @@ const gStoragePressureObserver = {
       msg = prefStrBundle.getFormattedString(descriptionStringID, [brandShortName]);
       buttons.push({
         label: prefStrBundle.getString(prefButtonLabelStringID),
         accessKey: prefStrBundle.getString(prefButtonAccesskeyStringID),
         callback(notificationBar, button) {
           // The advanced subpanes are only supported in the old organization, which will
           // be removed by bug 1349689.
           let win = gBrowser.ownerGlobal;
-          if (Services.prefs.getBoolPref("browser.preferences.useOldOrganization")) {
-            win.openAdvancedPreferences("networkTab", {origin: "storagePressure"});
-          } else {
-            win.openPreferences("panePrivacy", {origin: "storagePressure"});
-          }
+          win.openPreferences("panePrivacy", { origin: "storagePressure" });
         }
       });
     }
 
     notificationBox.appendNotification(
       msg, NOTIFICATION_VALUE, null, notificationBox.PRIORITY_WARNING_HIGH, buttons, null);
   }
 };
@@ -6530,23 +6526,17 @@ var OfflineApps = {
     if (browser && browser.messageManager) {
       browser.messageManager.sendAsyncMessage("OfflineApps:StartFetching", {
         docId,
       });
     }
   },
 
   manage() {
-    // The advanced subpanes are only supported in the old organization, which will
-    // be removed by bug 1349689.
-    if (Services.prefs.getBoolPref("browser.preferences.useOldOrganization")) {
-      openAdvancedPreferences("networkTab", {origin: "offlineApps"});
-    } else {
-      openPreferences("panePrivacy", {origin: "offlineApps"});
-    }
+    openPreferences("panePrivacy", { origin: "offlineApps" });
   },
 
   receiveMessage(msg) {
     switch (msg.name) {
       case "OfflineApps:CheckUsage":
         let uri = makeURI(msg.data.uri);
         if (this._usedMoreThanWarnQuota(uri)) {
           this.warnUsage(msg.target, uri);

--- a/browser/base/content/test/alerts/browser_notification_open_settings.js
+++ b/browser/base/content/test/alerts/browser_notification_open_settings.js
@@ -1,58 +1,40 @@
 "use strict";
 
 var notificationURL = "http://example.org/browser/browser/base/content/test/alerts/file_dom_notifications.html";
-var useOldPrefs = Services.prefs.getBoolPref("browser.preferences.useOldOrganization");
-var expectedURL = useOldPrefs ? "about:preferences#content"
-                              : "about:preferences#privacy";
-
+var expectedURL = "about:preferences#privacy";
 
 add_task(async function test_settingsOpen_observer() {
   info("Opening a dummy tab so openPreferences=>switchToTabHavingURI doesn't use the blank tab.");
   await BrowserTestUtils.withNewTab({
     gBrowser,
     url: "about:robots"
   }, async function dummyTabTask(aBrowser) {
-    // Ensure preferences is loaded before removing the tab. In the "new prefs", all categories
-    // get initialized on page load since we need to be able to search them. Sync is *very*
-    // slow to load and therefore we need to wait for it to load when testing the "new prefs".
-    // For "old prefs" we only load the actual visited categories so we don't have this problem,
-    // as well, the "sync-pane-loaded" notification is not sent on "old prefs".
-    let syncPaneLoadedPromise = useOldPrefs || TestUtils.topicObserved("sync-pane-loaded", () => true);
-
     let tabPromise = BrowserTestUtils.waitForNewTab(gBrowser, expectedURL);
     info("simulate a notifications-open-settings notification");
     let uri = NetUtil.newURI("https://example.com");
     let principal = Services.scriptSecurityManager.createCodebasePrincipal(uri, {});
     Services.obs.notifyObservers(principal, "notifications-open-settings");
     let tab = await tabPromise;
     ok(tab, "The notification settings tab opened");
-    await syncPaneLoadedPromise;
     await BrowserTestUtils.removeTab(tab);
   });
 });
 
 add_task(async function test_settingsOpen_button() {
   let pm = Services.perms;
   info("Adding notification permission");
   pm.add(makeURI(notificationURL), "desktop-notification", pm.ALLOW_ACTION);
 
   try {
     await BrowserTestUtils.withNewTab({
       gBrowser,
       url: notificationURL
     }, async function tabTask(aBrowser) {
-      // Ensure preferences is loaded before removing the tab. In the "new prefs", all categories
-      // get initialized on page load since we need to be able to search them. Sync is *very*
-      // slow to load and therefore we need to wait for it to load when testing the "new prefs".
-      // For "old prefs" we only load the actual visited categories so we don't have this problem,
-      // as well, the "sync-pane-loaded" notification is not sent on "old prefs".
-      let syncPaneLoadedPromise = useOldPrefs || TestUtils.topicObserved("sync-pane-loaded", () => true);
-
       info("Waiting for notification");
       await openNotification(aBrowser, "showNotification2");
 
       let alertWindow = Services.wm.getMostRecentWindow("alert:alert");
       if (!alertWindow) {
         ok(true, "Notifications don't use XUL windows on all platforms.");
         await closeNotification(aBrowser);
         return;
@@ -62,17 +44,16 @@ add_task(async function test_settingsOpe
       let tabPromise = BrowserTestUtils.waitForNewTab(gBrowser, expectedURL);
       let openSettingsMenuItem = alertWindow.document.getElementById("openSettingsMenuItem");
       openSettingsMenuItem.click();
 
       info("Waiting for notification settings tab");
       let tab = await tabPromise;
       ok(tab, "The notification settings tab opened");
 
-      await syncPaneLoadedPromise;
       await closePromise;
       await BrowserTestUtils.removeTab(tab);
     });
   } finally {
     info("Removing notification permission");
     pm.remove(makeURI(notificationURL), "desktop-notification");
   }
 });

--- a/browser/base/content/test/general/browser_datachoices_notification.js
+++ b/browser/base/content/test/general/browser_datachoices_notification.js
@@ -78,25 +78,20 @@ function triggerInfoBar(expectedTimeoutM
 }
 
 var checkInfobarButton = async function(aNotification) {
   // Check that the button on the data choices infobar does the right thing.
   let buttons = aNotification.getElementsByTagName("button");
   Assert.equal(buttons.length, 1, "There is 1 button in the data reporting notification.");
   let button = buttons[0];
 
-  // Add an observer to ensure the "advanced" pane opened (but don't bother
-  // closing it - we close the entire window when done.)
-  let paneLoadedPromise = promiseTopicObserved("advanced-pane-loaded");
-
   // Click on the button.
   button.click();
 
   // Wait for the preferences panel to open.
-  await paneLoadedPromise;
   await promiseNextTick();
 };
 
 add_task(async function setup() {
   const bypassNotification = Preferences.get(PREF_BYPASS_NOTIFICATION, true);
   const currentPolicyVersion = Preferences.get(PREF_CURRENT_POLICY_VERSION, 1);
 
   // Register a cleanup function to reset our preferences.

--- a/browser/base/content/test/general/browser_offlineQuotaNotification.js
+++ b/browser/base/content/test/general/browser_offlineQuotaNotification.js
@@ -10,17 +10,16 @@ const URL = "http://mochi.test:8888/brow
 
 registerCleanupFunction(function() {
   // Clean up after ourself
   let uri = Services.io.newURI(URL);
   let principal = Services.scriptSecurityManager.createCodebasePrincipal(uri, {});
   Services.perms.removeFromPrincipal(principal, "offline-app");
   Services.prefs.clearUserPref("offline-apps.quota.warn");
   Services.prefs.clearUserPref("offline-apps.allow_by_default");
-  Services.prefs.clearUserPref("browser.preferences.useOldOrganization");
   let {OfflineAppCacheHelper} = Components.utils.import("resource:///modules/offlineAppCache.jsm", {});
   OfflineAppCacheHelper.clear();
 });
 
 // Same as the other one, but for in-content preferences
 function checkInContentPreferences(win) {
   let doc = win.document;
   let sel = doc.getElementById("categories").selectedItems[0].id;
@@ -29,17 +28,16 @@ function checkInContentPreferences(win) 
   // all good, we are done.
   win.close();
   finish();
 }
 
 function test() {
   waitForExplicitFinish();
 
-  Services.prefs.setBoolPref("browser.preferences.useOldOrganization", false);
   Services.prefs.setBoolPref("offline-apps.allow_by_default", false);
 
   // Open a new tab.
   gBrowser.selectedTab = BrowserTestUtils.addTab(gBrowser, URL);
   registerCleanupFunction(() => gBrowser.removeCurrentTab());
 
 
   Promise.all([

--- a/browser/base/content/test/general/browser_storagePressure_notification.js
+++ b/browser/base/content/test/general/browser_storagePressure_notification.js
@@ -8,50 +8,23 @@ function notifyStoragePressure(usage = 1
   let usageWrapper = Cc["@mozilla.org/supports-PRUint64;1"]
                      .createInstance(Ci.nsISupportsPRUint64);
   usageWrapper.data = usage;
   Services.obs.notifyObservers(usageWrapper, "QuotaManager::StoragePressure");
   return notifyPromise;
 }
 
 function openAboutPrefPromise() {
-  let useOldOrganization = Services.prefs.getBoolPref("browser.preferences.useOldOrganization");
-  let targetURL = useOldOrganization ? "about:preferences#advanced" : "about:preferences#privacy";
   let promises = [
-    BrowserTestUtils.waitForLocationChange(gBrowser, targetURL),
-    TestUtils.topicObserved("advanced-pane-loaded", () => true)
+    BrowserTestUtils.waitForLocationChange(gBrowser, "about:preferences#privacy"),
+    TestUtils.topicObserved("privacy-pane-loaded", () => true)
   ];
   return Promise.all(promises);
 }
 
-async function testOverUsageThresholdNotification() {
-  await SpecialPowers.pushPrefEnv({set: [["browser.storageManager.enabled", true]]});
-  await SpecialPowers.pushPrefEnv({set: [["browser.storageManager.pressureNotification.minIntervalMS", 0]]});
-  let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser, "https://example.com");
-
-  const BYTES_IN_GIGABYTE = 1073741824;
-  const USAGE_THRESHOLD_BYTES = BYTES_IN_GIGABYTE *
-    Services.prefs.getIntPref("browser.storageManager.pressureNotification.usageThresholdGB");
-  await notifyStoragePressure(USAGE_THRESHOLD_BYTES);
-  let notificationbox = document.getElementById("high-priority-global-notificationbox");
-  let notification = notificationbox.getNotificationWithValue("storage-pressure-notification");
-  ok(notification instanceof XULElement, "Should display storage pressure notification");
-
-  let prefBtn = notification.getElementsByTagName("button")[1];
-  let aboutPrefPromise = openAboutPrefPromise();
-  prefBtn.doCommand();
-  await aboutPrefPromise;
-  let aboutPrefTab = gBrowser.selectedTab;
-  let prefDoc = gBrowser.selectedBrowser.contentDocument;
-  let siteDataGroup = prefDoc.getElementById("siteDataGroup");
-  is_element_visible(siteDataGroup, "Should open to the siteDataGroup section in about:preferences");
-  await BrowserTestUtils.removeTab(aboutPrefTab);
-  await BrowserTestUtils.removeTab(tab);
-}
-
 // Test only displaying notification once within the given interval
 add_task(async function() {
   const TEST_NOTIFICATION_INTERVAL_MS = 2000;
   await SpecialPowers.pushPrefEnv({set: [["browser.storageManager.enabled", true]]});
   await SpecialPowers.pushPrefEnv({set: [["browser.storageManager.pressureNotification.minIntervalMS", TEST_NOTIFICATION_INTERVAL_MS]]});
 
   await notifyStoragePressure();
   let notificationbox = document.getElementById("high-priority-global-notificationbox");
@@ -67,22 +40,38 @@ add_task(async function() {
   await notifyStoragePressure();
   notification = notificationbox.getNotificationWithValue("storage-pressure-notification");
   ok(notification instanceof XULElement, "Should display storage pressure notification after the given interval");
   notification.close();
 });
 
 // Test guiding user to the about:preferences when usage exceeds the given threshold
 add_task(async function() {
-  // Test for the old about:preferences
-  await SpecialPowers.pushPrefEnv({set: [["browser.preferences.useOldOrganization", true]]});
-  await testOverUsageThresholdNotification();
-  // Test for the new about:preferences
-  await SpecialPowers.pushPrefEnv({set: [["browser.preferences.useOldOrganization", false]]});
-  await testOverUsageThresholdNotification();
+  await SpecialPowers.pushPrefEnv({ set: [["browser.storageManager.enabled", true]] });
+  await SpecialPowers.pushPrefEnv({ set: [["browser.storageManager.pressureNotification.minIntervalMS", 0]] });
+  let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser, "https://example.com");
+
+  const BYTES_IN_GIGABYTE = 1073741824;
+  const USAGE_THRESHOLD_BYTES = BYTES_IN_GIGABYTE *
+    Services.prefs.getIntPref("browser.storageManager.pressureNotification.usageThresholdGB");
+  await notifyStoragePressure(USAGE_THRESHOLD_BYTES);
+  let notificationbox = document.getElementById("high-priority-global-notificationbox");
+  let notification = notificationbox.getNotificationWithValue("storage-pressure-notification");
+  ok(notification instanceof XULElement, "Should display storage pressure notification");
+
+  let prefBtn = notification.getElementsByTagName("button")[1];
+  let aboutPrefPromise = openAboutPrefPromise();
+  prefBtn.doCommand();
+  await aboutPrefPromise;
+  let aboutPrefTab = gBrowser.selectedTab;
+  let prefDoc = gBrowser.selectedBrowser.contentDocument;
+  let siteDataGroup = prefDoc.getElementById("siteDataGroup");
+  is_element_visible(siteDataGroup, "Should open to the siteDataGroup section in about:preferences");
+  await BrowserTestUtils.removeTab(aboutPrefTab);
+  await BrowserTestUtils.removeTab(tab);
 });
 
 // Test not displaying the 2nd notification if one is already being displayed
 add_task(async function() {
   const TEST_NOTIFICATION_INTERVAL_MS = 0;
   await SpecialPowers.pushPrefEnv({set: [["browser.storageManager.enabled", true]]});
   await SpecialPowers.pushPrefEnv({set: [["browser.storageManager.pressureNotification.minIntervalMS", TEST_NOTIFICATION_INTERVAL_MS]]});
 

--- a/browser/base/content/test/urlbar/browser_urlbarAboutHomeLoading.js
+++ b/browser/base/content/test/urlbar/browser_urlbarAboutHomeLoading.js
@@ -6,17 +6,17 @@ const {TabStateFlusher} = Cu.import("res
 /**
  * Test what happens if loading a URL that should clear the
  * location bar after a parent process URL.
  */
 add_task(async function clearURLBarAfterParentProcessURL() {
   let tab = await new Promise(resolve => {
     gBrowser.selectedTab = BrowserTestUtils.addTab(gBrowser, "about:preferences");
     let newTabBrowser = gBrowser.getBrowserForTab(gBrowser.selectedTab);
-    newTabBrowser.addEventListener("Initialized", function() {
+    newTabBrowser.addEventListener("Initialized", async function() {
       resolve(gBrowser.selectedTab);
     }, {capture: true, once: true});
   });
   document.getElementById("home-button").click();
   await BrowserTestUtils.browserLoaded(tab.linkedBrowser);
   is(gURLBar.value, "", "URL bar should be empty");
   is(tab.linkedBrowser.userTypedValue, null, "The browser should have no recorded userTypedValue");
   await BrowserTestUtils.removeTab(tab);
@@ -25,17 +25,17 @@ add_task(async function clearURLBarAfter
 /**
  * Same as above, but open the tab without passing the URL immediately
  * which changes behaviour in tabbrowser.xml.
  */
 add_task(async function clearURLBarAfterParentProcessURLInExistingTab() {
   let tab = await new Promise(resolve => {
     gBrowser.selectedTab = BrowserTestUtils.addTab(gBrowser);
     let newTabBrowser = gBrowser.getBrowserForTab(gBrowser.selectedTab);
-    newTabBrowser.addEventListener("Initialized", function() {
+    newTabBrowser.addEventListener("Initialized", async function() {
       resolve(gBrowser.selectedTab);
     }, {capture: true, once: true});
     newTabBrowser.loadURI("about:preferences");
   });
   document.getElementById("home-button").click();
   await BrowserTestUtils.browserLoaded(tab.linkedBrowser);
   is(gURLBar.value, "", "URL bar should be empty");
   is(tab.linkedBrowser.userTypedValue, null, "The browser should have no recorded userTypedValue");

--- a/browser/base/content/utilityOverlay.js
+++ b/browser/base/content/utilityOverlay.js
@@ -729,27 +729,16 @@ function openAboutDialog() {
 
 function openPreferences(paneID, extraArgs) {
   let histogram = Services.telemetry.getHistogramById("FX_PREFERENCES_OPENED_VIA");
   if (extraArgs && extraArgs.origin) {
     histogram.add(extraArgs.origin);
   } else {
     histogram.add("other");
   }
-  function switchToAdvancedSubPane(doc) {
-    if (extraArgs && extraArgs.advancedTab) {
-      // After the Preferences reorg works in Bug 1335907, no more advancedPrefs element.
-      // The old Preference is pref-off behind `browser.preferences.useOldOrganization` on Nightly.
-      // During the transition between the old and new Preferences, should do checking before proceeding.
-      let advancedPaneTabs = doc.getElementById("advancedPrefs");
-      if (advancedPaneTabs) {
-        advancedPaneTabs.selectedTab = doc.getElementById(extraArgs.advancedTab);
-      }
-    }
-  }
 
   // This function is duplicated from preferences.js.
   function internalPrefCategoryNameToFriendlyName(aName) {
     return (aName || "").replace(/^pane./, function(toReplace) { return toReplace[4].toLowerCase(); });
   }
 
   let win = Services.wm.getMostRecentWindow("navigator:browser");
   let friendlyCategoryName = internalPrefCategoryNameToFriendlyName(paneID);
@@ -759,64 +748,56 @@ function openPreferences(paneID, extraAr
     let urlParams = extraArgs.urlParams;
     for (let name in urlParams) {
       if (urlParams[name] !== undefined) {
         params.set(name, urlParams[name]);
       }
     }
   }
   let preferencesURL = "about:preferences" + (params ? "?" + params : "") +
-                       (friendlyCategoryName ? "#" + friendlyCategoryName : "");
+    (friendlyCategoryName ? "#" + friendlyCategoryName : "");
   let newLoad = true;
   let browser = null;
   if (!win) {
     const Cc = Components.classes;
     const Ci = Components.interfaces;
     let windowArguments = Cc["@mozilla.org/array;1"]
-                            .createInstance(Ci.nsIMutableArray);
+      .createInstance(Ci.nsIMutableArray);
     let supportsStringPrefURL = Cc["@mozilla.org/supports-string;1"]
-                                  .createInstance(Ci.nsISupportsString);
+      .createInstance(Ci.nsISupportsString);
     supportsStringPrefURL.data = preferencesURL;
     windowArguments.appendElement(supportsStringPrefURL);
 
     win = Services.ww.openWindow(null, Services.prefs.getCharPref("browser.chromeURL"),
-                                 "_blank", "chrome,dialog=no,all", windowArguments);
+      "_blank", "chrome,dialog=no,all", windowArguments);
   } else {
     let shouldReplaceFragment = friendlyCategoryName ? "whenComparingAndReplace" : "whenComparing";
     newLoad = !win.switchToTabHavingURI(preferencesURL, true, {
       ignoreFragment: shouldReplaceFragment,
       replaceQueryString: true,
       triggeringPrincipal: Services.scriptSecurityManager.getSystemPrincipal(),
     });
     browser = win.gBrowser.selectedBrowser;
   }
 
   if (newLoad) {
-    Services.obs.addObserver(function advancedPaneLoadedObs(prefWin, topic, data) {
+    Services.obs.addObserver(function panesLoadedObs(prefWin, topic, data) {
       if (!browser) {
         browser = win.gBrowser.selectedBrowser;
       }
       if (prefWin != browser.contentWindow) {
         return;
       }
-      Services.obs.removeObserver(advancedPaneLoadedObs, "advanced-pane-loaded");
-      switchToAdvancedSubPane(browser.contentDocument);
-    }, "advanced-pane-loaded");
-  } else {
-    if (paneID) {
-      browser.contentWindow.gotoPref(paneID);
-    }
-    switchToAdvancedSubPane(browser.contentDocument);
+      Services.obs.removeObserver(panesLoadedObs, "sync-pane-loaded");
+    }, "sync-pane-loaded");
+  } else if (paneID) {
+    browser.contentWindow.gotoPref(paneID);
   }
 }
 
-function openAdvancedPreferences(tabID, origin) {
-  openPreferences("paneAdvanced", { "advancedTab": tabID, origin });
-}
-
 /**
  * Opens the troubleshooting information (about:support) page for this version
  * of the application.
  */
 function openTroubleshootingPage() {
   openUILinkIn("about:support", "tab");
 }
 

--- a/browser/components/about/AboutRedirector.cpp
+++ b/browser/components/about/AboutRedirector.cpp
@@ -16,17 +16,16 @@
 #include "mozilla/Preferences.h"
 #include "nsServiceManagerUtils.h"
 
 namespace mozilla {
 namespace browser {
 
 NS_IMPL_ISUPPORTS(AboutRedirector, nsIAboutModule)
 
-bool AboutRedirector::sUseOldPreferences = false;
 bool AboutRedirector::sActivityStreamEnabled = false;
 bool AboutRedirector::sActivityStreamAboutHomeEnabled = false;
 
 struct RedirEntry {
   const char* id;
   const char* url;
   uint32_t flags;
 };
@@ -145,38 +144,30 @@ AboutRedirector::NewChannel(nsIURI* aURI
   NS_ASSERTION(result, "must not be null");
 
   nsAutoCString path = GetAboutModuleName(aURI);
 
   nsresult rv;
   nsCOMPtr<nsIIOService> ioService = do_GetIOService(&rv);
   NS_ENSURE_SUCCESS(rv, rv);
 
-  static bool sPrefCacheInited = false;
-  if (!sPrefCacheInited) {
-    Preferences::AddBoolVarCache(&sUseOldPreferences,
-                                 "browser.preferences.useOldOrganization");
-    sPrefCacheInited = true;
-  }
   LoadActivityStreamPrefs();
 
   for (auto & redir : kRedirMap) {
     if (!strcmp(path.get(), redir.id)) {
       nsAutoCString url;
 
       if (path.EqualsLiteral("newtab") ||
           (path.EqualsLiteral("home") && sActivityStreamEnabled && sActivityStreamAboutHomeEnabled)) {
         // let the aboutNewTabService decide where to redirect
         nsCOMPtr<nsIAboutNewTabService> aboutNewTabService =
           do_GetService("@mozilla.org/browser/aboutnewtab-service;1", &rv);
         NS_ENSURE_SUCCESS(rv, rv);
         rv = aboutNewTabService->GetDefaultURL(url);
         NS_ENSURE_SUCCESS(rv, rv);
-      } else if (path.EqualsLiteral("preferences") && !sUseOldPreferences) {
-        url.AssignASCII("chrome://browser/content/preferences/in-content-new/preferences.xul");
       }
       // fall back to the specified url in the map
       if (url.IsEmpty()) {
         url.AssignASCII(redir.url);
       }
 
       nsCOMPtr<nsIChannel> tempChannel;
       nsCOMPtr<nsIURI> tempURI;

--- a/browser/components/about/AboutRedirector.h
+++ b/browser/components/about/AboutRedirector.h
@@ -21,17 +21,16 @@ public:
 
   static nsresult
     Create(nsISupports *aOuter, REFNSIID aIID, void **aResult);
 
 protected:
   virtual ~AboutRedirector() {}
 
 private:
-  static bool sUseOldPreferences;
   static bool sActivityStreamEnabled;
   static bool sActivityStreamAboutHomeEnabled;
 
   static void LoadActivityStreamPrefs();
 };
 
 } // namespace browser
 } // namespace mozilla

--- a/browser/components/customizableui/test/browser_1087303_button_preferences.js
+++ b/browser/components/customizableui/test/browser_1087303_button_preferences.js
@@ -39,17 +39,18 @@ add_task(function asyncCleanup() {
 function waitForPageLoad(aTab) {
   return new Promise((resolve, reject) => {
 
     let timeoutId = setTimeout(() => {
       aTab.linkedBrowser.removeEventListener("load", onTabLoad, true);
       reject("Page didn't load within " + 20000 + "ms");
     }, 20000);
 
-    function onTabLoad(event) {
+    async function onTabLoad(event) {
       clearTimeout(timeoutId);
       aTab.linkedBrowser.removeEventListener("load", onTabLoad, true);
       info("Tab event received: load");
       resolve();
-   }
+    }
+
     aTab.linkedBrowser.addEventListener("load", onTabLoad, true, true);
   });
 }

--- a/browser/components/customizableui/test/browser_synced_tabs_menu.js
+++ b/browser/components/customizableui/test/browser_synced_tabs_menu.js
@@ -87,17 +87,17 @@ async function openPrefsFromMenuPanel(ex
   let subpanel = document.getElementById(expectedPanelId)
   ok(!subpanel.hidden, "sync setup element is visible");
 
   // Find and click the "setup" button.
   let setupButton = subpanel.querySelector(".PanelUI-remotetabs-prefs-button");
   setupButton.click();
 
   await new Promise(resolve => {
-    let handler = (e) => {
+    let handler = async(e) => {
       if (e.originalTarget != gBrowser.selectedBrowser.contentDocument ||
           e.target.location.href == "about:blank") {
         info("Skipping spurious 'load' event for " + e.target.location.href);
         return;
       }
       gBrowser.selectedBrowser.removeEventListener("load", handler, true);
       resolve();
     }

--- a/browser/components/feeds/FeedWriter.js
+++ b/browser/components/feeds/FeedWriter.js
@@ -816,17 +816,17 @@ FeedWriter.prototype = {
       // window object.
       return;
     }
     LOG(`received message from parent ${msg.name}`);
     switch (msg.name) {
       case "FeedWriter:PreferenceUpdated":
         // This is called when browser-feeds.js spots a pref change
         // This will happen when
-        // - about:preferences#applications changes
+        // - about:preferences#general changes
         // - another feed reader page changes the preference
         // - when this page itself changes the select and there isn't a redirect
         //   bookmarks and launching an external app means the page stays open after subscribe
         const feedType = this._getFeedType();
         LOG(`Got prefChange! ${JSON.stringify(msg.data)} current type: ${feedType}`);
         let feedTypePref = msg.data.default;
         if (feedType in msg.data) {
           feedTypePref = msg.data[feedType];

--- a/browser/components/nsBrowserGlue.js
+++ b/browser/components/nsBrowserGlue.js
@@ -296,21 +296,17 @@ BrowserGlue.prototype = {
     Cu.import("resource://services-sync/main.js");
     Weave.Service.scheduler.delayedAutoConnect(delay);
   },
 
   // nsIObserver implementation
   observe: function BG_observe(subject, topic, data) {
     switch (topic) {
       case "notifications-open-settings":
-        if (Services.prefs.getBoolPref("browser.preferences.useOldOrganization")) {
-          this._openPreferences("content", { origin: "notifOpenSettings" });
-        } else {
-          this._openPreferences("privacy", { origin: "notifOpenSettings" });
-        }
+        this._openPreferences("privacy", { origin: "notifOpenSettings" });
         break;
       case "prefservice:after-app-defaults":
         this._onAppDefaults();
         break;
       case "final-ui-startup":
         this._beforeUIStartup();
         break;
       case "browser-delayed-startup-finished":

--- a/browser/components/preferences/applicationManager.js
+++ b/browser/components/preferences/applicationManager.js
@@ -1,35 +1,25 @@
 // This Source Code Form is subject to the terms of the Mozilla Public
 // License, v. 2.0. If a copy of the MPL was not distributed with this
 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
-/* import-globals-from in-content/applications.js */
+/* import-globals-from in-content/main.js */
 
 var Cc = Components.classes;
 var Ci = Components.interfaces;
 
 var gAppManagerDialog = {
   _removed: [],
 
   init: function appManager_init() {
     this.handlerInfo = window.arguments[0];
-    // The applicationManager will be used
-    // in in-content's gApplicationsPane and in-content-new's gMainPane.
-    // Remove this once we use the in-content-new preferences page.
-    var pane;
-    if (Services.prefs.getBoolPref("browser.preferences.useOldOrganization")) {
-      Services.scriptloader.loadSubScript("chrome://browser/content/preferences/in-content/applications.js",
-                                          window);
-      pane = gApplicationsPane;
-    } else {
-      Services.scriptloader.loadSubScript("chrome://browser/content/preferences/in-content-new/main.js",
-                                          window);
-      pane = gMainPane;
-    }
+    Services.scriptloader.loadSubScript("chrome://browser/content/preferences/in-content/main.js",
+      window);
+    var pane = gMainPane;
     var bundle = document.getElementById("appManagerBundle");
     var contentText;
     if (this.handlerInfo.type == TYPE_MAYBE_FEED)
       contentText = bundle.getString("handleWebFeeds");
     else {
       var description = pane._describeType(this.handlerInfo);
       var key =
         (this.handlerInfo.wrappedHandlerInfo instanceof Ci.nsIMIMEInfo) ? "handleFile"

--- a/browser/components/preferences/handlers.xml
+++ b/browser/components/preferences/handlers.xml
@@ -1,14 +1,14 @@
 <?xml version="1.0"?>
 
 <!-- This Source Code Form is subject to the terms of the Mozilla Public
    - License, v. 2.0. If a copy of the MPL was not distributed with this
    - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
-<!-- import-globals-from in-content/applications.js -->
+<!-- import-globals-from in-content/main.js -->
 
 <!DOCTYPE overlay [
   <!ENTITY % brandDTD SYSTEM "chrome://branding/locale/brand.dtd">
   <!ENTITY % applicationsDTD SYSTEM "chrome://browser/locale/preferences/applications.dtd">
   <!ENTITY % containersDTD SYSTEM "chrome://browser/locale/preferences/containers.dtd">
   %brandDTD;
   %applicationsDTD;
   %containersDTD;
@@ -51,32 +51,26 @@
         <xul:hbox flex="1" align="center" xbl:inherits="tooltiptext=typeDescription">
           <xul:image src="moz-icon://goat?size=16" class="typeIcon"
                      xbl:inherits="src=typeIcon" height="16" width="16"/>
           <xul:label flex="1" crop="end" xbl:inherits="value=typeDescription"/>
         </xul:hbox>
         <xul:hbox flex="1">
           <xul:menulist class="actionsMenu" flex="1" crop="end" selectedIndex="1"
                         xbl:inherits="tooltiptext=actionDescription"
-                        oncommand="Services.prefs.getBoolPref('browser.preferences.useOldOrganization') ?
-                          gApplicationsPane.onSelectAction(event.originalTarget) :
-                          gMainPane.onSelectAction(event.originalTarget)">
+                        oncommand="gMainPane.onSelectAction(event.originalTarget)">
             <xul:menupopup/>
           </xul:menulist>
         </xul:hbox>
       </xul:hbox>
     </content>
 
     <implementation>
       <constructor>
-        if (Services.prefs.getBoolPref("browser.preferences.useOldOrganization")) {
-          gApplicationsPane.rebuildActionsMenu();
-        } else {
-          gMainPane.rebuildActionsMenu();
-        }
+        gMainPane.rebuildActionsMenu();
       </constructor>
     </implementation>
 
   </binding>
 
   <binding id="container">
     <content>
       <xul:hbox flex="1" equalsize="always">

deleted file mode 100644
--- a/browser/components/preferences/in-content-new/containers.js
+++ /dev/null
@@ -1,99 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this file,
- * You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-/* import-globals-from preferences.js */
-
-Components.utils.import("resource://gre/modules/AppConstants.jsm");
-Components.utils.import("resource://gre/modules/ContextualIdentityService.jsm");
-
-const containersBundle = Services.strings.createBundle("chrome://browser/locale/preferences/containers.properties");
-
-const defaultContainerIcon = "fingerprint";
-const defaultContainerColor = "blue";
-
-let gContainersPane = {
-
-  init() {
-    this._list = document.getElementById("containersView");
-
-    document.getElementById("backContainersLink").addEventListener("click", function() {
-      gotoPref("general");
-    });
-
-    this._rebuildView();
-  },
-
-  _rebuildView() {
-    const containers = ContextualIdentityService.getPublicIdentities();
-    while (this._list.firstChild) {
-      this._list.firstChild.remove();
-    }
-    for (let container of containers) {
-      let item = document.createElement("richlistitem");
-      item.setAttribute("containerName", ContextualIdentityService.getUserContextLabel(container.userContextId));
-      item.setAttribute("containerIcon", container.icon);
-      item.setAttribute("containerColor", container.color);
-      item.setAttribute("userContextId", container.userContextId);
-
-      this._list.appendChild(item);
-    }
-  },
-
-  async onRemoveClick(button) {
-    let userContextId = parseInt(button.getAttribute("value"), 10);
-
-    let count = ContextualIdentityService.countContainerTabs(userContextId);
-    if (count > 0) {
-      let bundlePreferences = document.getElementById("bundlePreferences");
-
-      let title = bundlePreferences.getString("removeContainerAlertTitle");
-      let message = PluralForm.get(count, bundlePreferences.getString("removeContainerMsg"))
-                              .replace("#S", count)
-      let okButton = bundlePreferences.getString("removeContainerOkButton");
-      let cancelButton = bundlePreferences.getString("removeContainerButton2");
-
-      let buttonFlags = (Ci.nsIPrompt.BUTTON_TITLE_IS_STRING * Ci.nsIPrompt.BUTTON_POS_0) +
-                        (Ci.nsIPrompt.BUTTON_TITLE_IS_STRING * Ci.nsIPrompt.BUTTON_POS_1);
-
-      let rv = Services.prompt.confirmEx(window, title, message, buttonFlags,
-                                         okButton, cancelButton, null, null, {});
-      if (rv != 0) {
-        return;
-      }
-
-      await ContextualIdentityService.closeContainerTabs(userContextId);
-    }
-
-    ContextualIdentityService.remove(userContextId);
-    this._rebuildView();
-  },
-
-  onPreferenceClick(button) {
-    this.openPreferenceDialog(button.getAttribute("value"));
-  },
-
-  onAddButtonClick(button) {
-    this.openPreferenceDialog(null);
-  },
-
-  openPreferenceDialog(userContextId) {
-    let identity = {
-      name: "",
-      icon: defaultContainerIcon,
-      color: defaultContainerColor
-    };
-    let title;
-    if (userContextId) {
-      identity = ContextualIdentityService.getPublicIdentityFromId(userContextId);
-      // This is required to get the translation string from defaults
-      identity.name = ContextualIdentityService.getUserContextLabel(identity.userContextId);
-      title = containersBundle.formatStringFromName("containers.updateContainerTitle", [identity.name], 1);
-    }
-
-    const params = { userContextId, identity, windowTitle: title };
-    gSubDialog.open("chrome://browser/content/preferences/containers.xul",
-                     null, params);
-  }
-
-};

deleted file mode 100644
--- a/browser/components/preferences/in-content-new/containers.xul
+++ /dev/null
@@ -1,45 +0,0 @@
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-<!-- Containers panel -->
-
-<script type="application/javascript"
-        src="chrome://browser/content/preferences/in-content-new/containers.js"/>
-
-<preferences id="containerPreferences" hidden="true" data-category="paneContainer">
-  <!-- Containers -->
-  <preference id="privacy.userContext.enabled"
-              name="privacy.userContext.enabled"
-              type="bool"/>
-
-</preferences>
-
-<hbox hidden="true"
-      class="container-header-links"
-      data-category="paneContainers">
-  <label class="text-link" id="backContainersLink">&backLink2.label;</label>
-</hbox>
-
-<hbox id="header-containers"
-      class="header"
-      hidden="true"
-      data-category="paneContainers">
-  <label class="header-name" flex="1">&paneContainers.title;</label>
-</hbox>
-
-<!-- Containers -->
-<groupbox id="browserContainersGroupPane" data-category="paneContainers" hidden="true"
-          data-hidden-from-search="true" data-subpanel="true">
-  <vbox id="browserContainersbox">
-
-    <richlistbox id="containersView" orient="vertical" persist="lastSelectedType"
-                 flex="1">
-    </richlistbox>
-  </vbox>
-  <vbox>
-    <hbox flex="1">
-      <button onclick="gContainersPane.onAddButtonClick();" accesskey="&addButton.accesskey;" label="&addButton.label;"/>
-    </hbox>
-  </vbox>
-</groupbox>

deleted file mode 100644
--- a/browser/components/preferences/in-content-new/jar.mn
+++ /dev/null
@@ -1,15 +0,0 @@
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-browser.jar:
-   content/browser/preferences/in-content-new/preferences.js
-*  content/browser/preferences/in-content-new/preferences.xul
-   content/browser/preferences/in-content-new/subdialogs.js
-
-   content/browser/preferences/in-content-new/main.js
-   content/browser/preferences/in-content-new/search.js
-   content/browser/preferences/in-content-new/privacy.js
-   content/browser/preferences/in-content-new/containers.js
-   content/browser/preferences/in-content-new/sync.js
-   content/browser/preferences/in-content-new/findInPage.js

deleted file mode 100644
--- a/browser/components/preferences/in-content-new/main.js
+++ /dev/null
@@ -1,3263 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this file,
- * You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-/* import-globals-from preferences.js */
-/* import-globals-from ../../../../toolkit/mozapps/preferences/fontbuilder.js */
-/* import-globals-from ../../../base/content/aboutDialog-appUpdater.js */
-
-Components.utils.import("resource://gre/modules/Services.jsm");
-Components.utils.import("resource://gre/modules/Downloads.jsm");
-Components.utils.import("resource://gre/modules/FileUtils.jsm");
-Components.utils.import("resource:///modules/ShellService.jsm");
-Components.utils.import("resource:///modules/TransientPrefs.jsm");
-Components.utils.import("resource://gre/modules/Services.jsm");
-Components.utils.import("resource://gre/modules/AppConstants.jsm");
-Components.utils.import("resource://gre/modules/DownloadUtils.jsm");
-Components.utils.import("resource://gre/modules/LoadContextInfo.jsm");
-XPCOMUtils.defineLazyModuleGetter(this, "CloudStorage",
-                                  "resource://gre/modules/CloudStorage.jsm");
-
-// Constants & Enumeration Values
-const TYPE_MAYBE_FEED = "application/vnd.mozilla.maybe.feed";
-const TYPE_MAYBE_VIDEO_FEED = "application/vnd.mozilla.maybe.video.feed";
-const TYPE_MAYBE_AUDIO_FEED = "application/vnd.mozilla.maybe.audio.feed";
-const TYPE_PDF = "application/pdf";
-
-const PREF_PDFJS_DISABLED = "pdfjs.disabled";
-const TOPIC_PDFJS_HANDLER_CHANGED = "pdfjs:handlerChanged";
-
-const PREF_DISABLED_PLUGIN_TYPES = "plugin.disable_full_page_plugin_for_types";
-
-// Preferences that affect which entries to show in the list.
-const PREF_SHOW_PLUGINS_IN_LIST = "browser.download.show_plugins_in_list";
-const PREF_HIDE_PLUGINS_WITHOUT_EXTENSIONS =
-  "browser.download.hide_plugins_without_extensions";
-
-/*
- * Preferences where we store handling information about the feed type.
- *
- * browser.feeds.handler
- * - "bookmarks", "reader" (clarified further using the .default preference),
- *   or "ask" -- indicates the default handler being used to process feeds;
- *   "bookmarks" is obsolete; to specify that the handler is bookmarks,
- *   set browser.feeds.handler.default to "bookmarks";
- *
- * browser.feeds.handler.default
- * - "bookmarks", "client" or "web" -- indicates the chosen feed reader used
- *   to display feeds, either transiently (i.e., when the "use as default"
- *   checkbox is unchecked, corresponds to when browser.feeds.handler=="ask")
- *   or more permanently (i.e., the item displayed in the dropdown in Feeds
- *   preferences)
- *
- * browser.feeds.handler.webservice
- * - the URL of the currently selected web service used to read feeds
- *
- * browser.feeds.handlers.application
- * - nsIFile, stores the current client-side feed reading app if one has
- *   been chosen
- */
-const PREF_FEED_SELECTED_APP    = "browser.feeds.handlers.application";
-const PREF_FEED_SELECTED_WEB    = "browser.feeds.handlers.webservice";
-const PREF_FEED_SELECTED_ACTION = "browser.feeds.handler";
-const PREF_FEED_SELECTED_READER = "browser.feeds.handler.default";
-
-const PREF_VIDEO_FEED_SELECTED_APP    = "browser.videoFeeds.handlers.application";
-const PREF_VIDEO_FEED_SELECTED_WEB    = "browser.videoFeeds.handlers.webservice";
-const PREF_VIDEO_FEED_SELECTED_ACTION = "browser.videoFeeds.handler";
-const PREF_VIDEO_FEED_SELECTED_READER = "browser.videoFeeds.handler.default";
-
-const PREF_AUDIO_FEED_SELECTED_APP    = "browser.audioFeeds.handlers.application";
-const PREF_AUDIO_FEED_SELECTED_WEB    = "browser.audioFeeds.handlers.webservice";
-const PREF_AUDIO_FEED_SELECTED_ACTION = "browser.audioFeeds.handler";
-const PREF_AUDIO_FEED_SELECTED_READER = "browser.audioFeeds.handler.default";
-
-// The nsHandlerInfoAction enumeration values in nsIHandlerInfo identify
-// the actions the application can take with content of various types.
-// But since nsIHandlerInfo doesn't support plugins, there's no value
-// identifying the "use plugin" action, so we use this constant instead.
-const kActionUsePlugin = 5;
-
-const ICON_URL_APP = AppConstants.platform == "linux" ?
-                     "moz-icon://dummy.exe?size=16" :
-                     "chrome://browser/skin/preferences/application.png";
-
-// For CSS. Can be one of "ask", "save", "plugin" or "feed". If absent, the icon URL
-// was set by us to a custom handler icon and CSS should not try to override it.
-const APP_ICON_ATTR_NAME = "appHandlerIcon";
-
-XPCOMUtils.defineLazyModuleGetter(this, "OS",
-                                  "resource://gre/modules/osfile.jsm");
-
-if (AppConstants.E10S_TESTING_ONLY) {
-  XPCOMUtils.defineLazyModuleGetter(this, "UpdateUtils",
-                                    "resource://gre/modules/UpdateUtils.jsm");
-}
-
-if (AppConstants.MOZ_DEV_EDITION) {
-  XPCOMUtils.defineLazyModuleGetter(this, "fxAccounts",
-                                    "resource://gre/modules/FxAccounts.jsm");
-}
-
-var gMainPane = {
-  // The set of types the app knows how to handle.  A hash of HandlerInfoWrapper
-  // objects, indexed by type.
-  _handledTypes: {},
-
-  // The list of types we can show, sorted by the sort column/direction.
-  // An array of HandlerInfoWrapper objects.  We build this list when we first
-  // load the data and then rebuild it when users change a pref that affects
-  // what types we can show or change the sort column/direction.
-  // Note: this isn't necessarily the list of types we *will* show; if the user
-  // provides a filter string, we'll only show the subset of types in this list
-  // that match that string.
-  _visibleTypes: [],
-
-  // A count of the number of times each visible type description appears.
-  // We use these counts to determine whether or not to annotate descriptions
-  // with their types to distinguish duplicate descriptions from each other.
-  // A hash of integer counts, indexed by string description.
-  _visibleTypeDescriptionCount: {},
-
-
-  // Convenience & Performance Shortcuts
-
-  // These get defined by init().
-  _brandShortName: null,
-  _prefsBundle: null,
-  _list: null,
-  _filter: null,
-
-  _prefSvc: Cc["@mozilla.org/preferences-service;1"].
-            getService(Ci.nsIPrefBranch),
-
-  _mimeSvc: Cc["@mozilla.org/mime;1"].
-            getService(Ci.nsIMIMEService),
-
-  _helperAppSvc: Cc["@mozilla.org/uriloader/external-helper-app-service;1"].
-                 getService(Ci.nsIExternalHelperAppService),
-
-  _handlerSvc: Cc["@mozilla.org/uriloader/handler-service;1"].
-               getService(Ci.nsIHandlerService),
-
-  _ioSvc: Cc["@mozilla.org/network/io-service;1"].
-          getService(Ci.nsIIOService),
-
-  _backoffIndex: 0,
-
-  /**
-   * Initialization of this.
-   */
-  init() {
-    function setEventListener(aId, aEventType, aCallback) {
-      document.getElementById(aId)
-              .addEventListener(aEventType, aCallback.bind(gMainPane));
-    }
-
-    if (AppConstants.HAVE_SHELL_SERVICE) {
-      this.updateSetDefaultBrowser();
-      let win = Services.wm.getMostRecentWindow("navigator:browser");
-
-      // Exponential backoff mechanism will delay the polling times if user doesn't
-      // trigger SetDefaultBrowser for a long time.
-      let backoffTimes = [1000, 1000, 1000, 1000, 2000, 2000, 2000, 5000, 5000, 10000];
-
-      let pollForDefaultBrowser = () => {
-        let uri = win.gBrowser.currentURI.spec;
-
-        if ((uri == "about:preferences" || uri == "about:preferences#general") &&
-            document.visibilityState == "visible") {
-          this.updateSetDefaultBrowser();
-        }
-
-        // approximately a "requestIdleInterval"
-        window.setTimeout(() => {
-          window.requestIdleCallback(pollForDefaultBrowser);
-        }, backoffTimes[this._backoffIndex + 1 < backoffTimes.length ?
-                        this._backoffIndex++ : backoffTimes.length - 1]);
-      };
-
-      window.setTimeout(() => {
-        window.requestIdleCallback(pollForDefaultBrowser);
-      }, backoffTimes[this._backoffIndex]);
-    }
-
-    this.initBrowserContainers();
-    this.buildContentProcessCountMenuList();
-
-    let performanceSettingsLink = document.getElementById("performanceSettingsLearnMore");
-    let performanceSettingsUrl = Services.urlFormatter.formatURLPref("app.support.baseURL") + "performance";
-    performanceSettingsLink.setAttribute("href", performanceSettingsUrl);
-
-    this.updateDefaultPerformanceSettingsPref();
-
-    let defaultPerformancePref =
-      document.getElementById("browser.preferences.defaultPerformanceSettings.enabled");
-    defaultPerformancePref.addEventListener("change", () => {
-      this.updatePerformanceSettingsBox({duringChangeEvent: true});
-    });
-    this.updatePerformanceSettingsBox({duringChangeEvent: false});
-
-    // set up the "use current page" label-changing listener
-    this._updateUseCurrentButton();
-    window.addEventListener("focus", this._updateUseCurrentButton.bind(this));
-
-    this.updateBrowserStartupLastSession();
-
-    if (AppConstants.platform == "win") {
-      // Functionality for "Show tabs in taskbar" on Windows 7 and up.
-      try {
-        let sysInfo = Cc["@mozilla.org/system-info;1"].
-                      getService(Ci.nsIPropertyBag2);
-        let ver = parseFloat(sysInfo.getProperty("version"));
-        let showTabsInTaskbar = document.getElementById("showTabsInTaskbar");
-        showTabsInTaskbar.hidden = ver < 6.1;
-      } catch (ex) {}
-    }
-
-    // The "closing multiple tabs" and "opening multiple tabs might slow down
-    // &brandShortName;" warnings provide options for not showing these
-    // warnings again. When the user disabled them, we provide checkboxes to
-    // re-enable the warnings.
-    if (!TransientPrefs.prefShouldBeVisible("browser.tabs.warnOnClose"))
-      document.getElementById("warnCloseMultiple").hidden = true;
-    if (!TransientPrefs.prefShouldBeVisible("browser.tabs.warnOnOpen"))
-      document.getElementById("warnOpenMany").hidden = true;
-
-    setEventListener("browser.privatebrowsing.autostart", "change",
-                     gMainPane.updateBrowserStartupLastSession);
-    if (AppConstants.HAVE_SHELL_SERVICE) {
-      setEventListener("setDefaultButton", "command",
-                       gMainPane.setDefaultBrowser);
-    }
-    setEventListener("useCurrent", "command",
-                     gMainPane.setHomePageToCurrent);
-    setEventListener("useBookmark", "command",
-                     gMainPane.setHomePageToBookmark);
-    setEventListener("restoreDefaultHomePage", "command",
-                     gMainPane.restoreDefaultHomePage);
-    setEventListener("chooseLanguage", "command",
-      gMainPane.showLanguages);
-    setEventListener("translationAttributionImage", "click",
-      gMainPane.openTranslationProviderAttribution);
-    setEventListener("translateButton", "command",
-      gMainPane.showTranslationExceptions);
-    setEventListener("font.language.group", "change",
-      gMainPane._rebuildFonts);
-    setEventListener("advancedFonts", "command",
-      gMainPane.configureFonts);
-    setEventListener("colors", "command",
-      gMainPane.configureColors);
-    setEventListener("layers.acceleration.disabled", "change",
-      gMainPane.updateHardwareAcceleration);
-    setEventListener("connectionSettings", "command",
-      gMainPane.showConnections);
-    setEventListener("browserContainersCheckbox", "command",
-      gMainPane.checkBrowserContainers);
-    setEventListener("browserContainersSettings", "command",
-      gMainPane.showContainerSettings);
-
-    // Initializes the fonts dropdowns displayed in this pane.
-    this._rebuildFonts();
-
-    this.updateOnScreenKeyboardVisibility();
-
-    // Show translation preferences if we may:
-    const prefName = "browser.translation.ui.show";
-    if (Services.prefs.getBoolPref(prefName)) {
-      let row = document.getElementById("translationBox");
-      row.removeAttribute("hidden");
-      // Showing attribution only for Bing Translator.
-      Components.utils.import("resource:///modules/translation/Translation.jsm");
-      if (Translation.translationEngine == "bing") {
-        document.getElementById("bingAttribution").removeAttribute("hidden");
-      }
-    }
-
-    if (AppConstants.E10S_TESTING_ONLY) {
-      setEventListener("e10sAutoStart", "command",
-                       gMainPane.enableE10SChange);
-      let e10sCheckbox = document.getElementById("e10sAutoStart");
-
-      let e10sPref = document.getElementById("browser.tabs.remote.autostart");
-      let e10sTempPref = document.getElementById("e10sTempPref");
-      let e10sForceEnable = document.getElementById("e10sForceEnable");
-
-      let preffedOn = e10sPref.value || e10sTempPref.value || e10sForceEnable.value;
-
-      if (preffedOn) {
-        // The checkbox is checked if e10s is preffed on and enabled.
-        e10sCheckbox.checked = Services.appinfo.browserTabsRemoteAutostart;
-
-        // but if it's force disabled, then the checkbox is disabled.
-        e10sCheckbox.disabled = !Services.appinfo.browserTabsRemoteAutostart;
-      }
-    }
-
-    if (AppConstants.MOZ_DEV_EDITION) {
-      let uAppData = OS.Constants.Path.userApplicationDataDir;
-      let ignoreSeparateProfile = OS.Path.join(uAppData, "ignore-dev-edition-profile");
-
-      setEventListener("separateProfileMode", "command", gMainPane.separateProfileModeChange);
-      let separateProfileModeCheckbox = document.getElementById("separateProfileMode");
-      setEventListener("getStarted", "click", gMainPane.onGetStarted);
-
-      OS.File.stat(ignoreSeparateProfile).then(() => separateProfileModeCheckbox.checked = false,
-                                               () => separateProfileModeCheckbox.checked = true);
-
-      fxAccounts.getSignedInUser().then(data => {
-        document.getElementById("getStarted").selectedIndex = data ? 1 : 0;
-      })
-      .catch(Cu.reportError);
-    }
-
-    // Initialize the Firefox Updates section.
-    let version = AppConstants.MOZ_APP_VERSION_DISPLAY;
-
-    // Include the build ID if this is an "a#" (nightly) build
-    if (/a\d+$/.test(version)) {
-      let buildID = Services.appinfo.appBuildID;
-      let year = buildID.slice(0, 4);
-      let month = buildID.slice(4, 6);
-      let day = buildID.slice(6, 8);
-      version += ` (${year}-${month}-${day})`;
-    }
-
-    // Append "(32-bit)" or "(64-bit)" build architecture to the version number:
-    let bundle = Services.strings.createBundle("chrome://browser/locale/browser.properties");
-    let archResource = Services.appinfo.is64Bit
-                       ? "aboutDialog.architecture.sixtyFourBit"
-                       : "aboutDialog.architecture.thirtyTwoBit";
-    let arch = bundle.GetStringFromName(archResource);
-    version += ` (${arch})`;
-
-    document.getElementById("version").textContent = version;
-
-    // Show a release notes link if we have a URL.
-    let relNotesLink = document.getElementById("releasenotes");
-    let relNotesPrefType = Services.prefs.getPrefType("app.releaseNotesURL");
-    if (relNotesPrefType != Services.prefs.PREF_INVALID) {
-      let relNotesURL = Services.urlFormatter.formatURLPref("app.releaseNotesURL");
-      if (relNotesURL != "about:blank") {
-        relNotesLink.href = relNotesURL;
-        relNotesLink.hidden = false;
-      }
-    }
-
-    let distroId = Services.prefs.getCharPref("distribution.id", "");
-    if (distroId) {
-      let distroVersion = Services.prefs.getCharPref("distribution.version");
-
-      let distroIdField = document.getElementById("distributionId");
-      distroIdField.value = distroId + " - " + distroVersion;
-      distroIdField.hidden = false;
-
-      let distroAbout = Services.prefs.getStringPref("distribution.about", "");
-      if (distroAbout) {
-        let distroField = document.getElementById("distribution");
-        distroField.value = distroAbout;
-        distroField.hidden = false;
-      }
-    }
-
-    if (AppConstants.MOZ_UPDATER) {
-      gAppUpdater = new appUpdater();
-      let onUnload = () => {
-        window.removeEventListener("unload", onUnload);
-        Services.prefs.removeObserver("app.update.", this);
-      };
-      window.addEventListener("unload", onUnload);
-      Services.prefs.addObserver("app.update.", this);
-      this.updateReadPrefs();
-      setEventListener("updateRadioGroup", "command",
-                       gMainPane.updateWritePrefs);
-      setEventListener("showUpdateHistory", "command",
-                       gMainPane.showUpdates);
-    }
-
-    // Initilize Application section.
-    // Initialize shortcuts to some commonly accessed elements & values.
-    this._brandShortName =
-      document.getElementById("bundleBrand").getString("brandShortName");
-    this._prefsBundle = document.getElementById("bundlePreferences");
-    this._list = document.getElementById("handlersView");
-    this._filter = document.getElementById("filter");
-
-    // Observe preferences that influence what we display so we can rebuild
-    // the view when they change.
-    this._prefSvc.addObserver(PREF_SHOW_PLUGINS_IN_LIST, this);
-    this._prefSvc.addObserver(PREF_HIDE_PLUGINS_WITHOUT_EXTENSIONS, this);
-    this._prefSvc.addObserver(PREF_FEED_SELECTED_APP, this);
-    this._prefSvc.addObserver(PREF_FEED_SELECTED_WEB, this);
-    this._prefSvc.addObserver(PREF_FEED_SELECTED_ACTION, this);
-    this._prefSvc.addObserver(PREF_FEED_SELECTED_READER, this);
-
-    this._prefSvc.addObserver(PREF_VIDEO_FEED_SELECTED_APP, this);
-    this._prefSvc.addObserver(PREF_VIDEO_FEED_SELECTED_WEB, this);
-    this._prefSvc.addObserver(PREF_VIDEO_FEED_SELECTED_ACTION, this);
-    this._prefSvc.addObserver(PREF_VIDEO_FEED_SELECTED_READER, this);
-
-    this._prefSvc.addObserver(PREF_AUDIO_FEED_SELECTED_APP, this);
-    this._prefSvc.addObserver(PREF_AUDIO_FEED_SELECTED_WEB, this);
-    this._prefSvc.addObserver(PREF_AUDIO_FEED_SELECTED_ACTION, this);
-    this._prefSvc.addObserver(PREF_AUDIO_FEED_SELECTED_READER, this);
-
-    setEventListener("filter", "command", gMainPane.filter);
-    setEventListener("handlersView", "select",
-      gMainPane.onSelectionChanged);
-    setEventListener("typeColumn", "click", gMainPane.sort);
-    setEventListener("actionColumn", "click", gMainPane.sort);
-    setEventListener("chooseFolder", "command", gMainPane.chooseFolder);
-    setEventListener("browser.download.dir", "change", gMainPane.displayDownloadDirPref);
-    setEventListener("saveWhere", "command", gMainPane.handleSaveToCommand);
-
-    // Listen for window unload so we can remove our preference observers.
-    window.addEventListener("unload", this);
-
-    // Figure out how we should be sorting the list.  We persist sort settings
-    // across sessions, so we can't assume the default sort column/direction.
-    // XXX should we be using the XUL sort service instead?
-    if (document.getElementById("actionColumn").hasAttribute("sortDirection")) {
-      this._sortColumn = document.getElementById("actionColumn");
-      // The typeColumn element always has a sortDirection attribute,
-      // either because it was persisted or because the default value
-      // from the xul file was used.  If we are sorting on the other
-      // column, we should remove it.
-      document.getElementById("typeColumn").removeAttribute("sortDirection");
-    } else {
-      this._sortColumn = document.getElementById("typeColumn");
-    }
-
-    // Load the data and build the list of handlers.
-    // By doing this in a timeout, we let the preferences dialog resize itself
-    // to an appropriate size before we add a bunch of items to the list.
-    // Otherwise, if there are many items, and the Applications prefpane
-    // is the one that gets displayed when the user first opens the dialog,
-    // the dialog might stretch too much in an attempt to fit them all in.
-    // XXX Shouldn't we perhaps just set a max-height on the richlistbox?
-    var _delayedPaneLoad = function(self) {
-      self._loadData();
-      self._rebuildVisibleTypes();
-      self._sortVisibleTypes();
-      self._rebuildView();
-    }
-    setTimeout(_delayedPaneLoad, 0, this);
-
-    let browserBundle = document.getElementById("browserBundle");
-    appendSearchKeywords("browserContainersSettings", [
-      browserBundle.getString("userContextPersonal.label"),
-      browserBundle.getString("userContextWork.label"),
-      browserBundle.getString("userContextBanking.label"),
-      browserBundle.getString("userContextShopping.label"),
-    ]);
-
-    // Notify observers that the UI is now ready
-    Components.classes["@mozilla.org/observer-service;1"]
-              .getService(Components.interfaces.nsIObserverService)
-              .notifyObservers(window, "main-pane-loaded");
-  },
-
-  /**
-   * Show the Containers UI depending on the privacy.userContext.ui.enabled pref.
-   */
-  initBrowserContainers() {
-    if (!Services.prefs.getBoolPref("privacy.userContext.ui.enabled")) {
-      // The browserContainersGroup element has its own internal padding that
-      // is visible even if the browserContainersbox is visible, so hide the whole
-      // groupbox if the feature is disabled to prevent a gap in the preferences.
-      document.getElementById("browserContainersbox").setAttribute("data-hidden-from-search", "true");
-      return;
-    }
-
-    let link = document.getElementById("browserContainersLearnMore");
-    link.href = Services.urlFormatter.formatURLPref("app.support.baseURL") + "containers";
-
-    document.getElementById("browserContainersbox").hidden = false;
-
-    document.getElementById("browserContainersCheckbox").checked =
-      Services.prefs.getBoolPref("privacy.userContext.enabled");
-  },
-
-  isE10SEnabled() {
-    let e10sEnabled;
-    try {
-      let e10sStatus = Components.classes["@mozilla.org/supports-PRUint64;1"]
-                         .createInstance(Ci.nsISupportsPRUint64);
-      let appinfo = Services.appinfo.QueryInterface(Ci.nsIObserver);
-      appinfo.observe(e10sStatus, "getE10SBlocked", "");
-      e10sEnabled = e10sStatus.data < 2;
-    } catch (e) {
-      e10sEnabled = false;
-    }
-
-    return e10sEnabled;
-  },
-
-  enableE10SChange() {
-    if (AppConstants.E10S_TESTING_ONLY) {
-      let e10sCheckbox = document.getElementById("e10sAutoStart");
-      let e10sPref = document.getElementById("browser.tabs.remote.autostart");
-      let e10sTempPref = document.getElementById("e10sTempPref");
-
-      let prefsToChange;
-      if (e10sCheckbox.checked) {
-        // Enabling e10s autostart
-        prefsToChange = [e10sPref];
-      } else {
-        // Disabling e10s autostart
-        prefsToChange = [e10sPref];
-        if (e10sTempPref.value) {
-         prefsToChange.push(e10sTempPref);
-        }
-      }
-
-      let buttonIndex = confirmRestartPrompt(e10sCheckbox.checked, 0,
-                                             true, false);
-      if (buttonIndex == CONFIRM_RESTART_PROMPT_RESTART_NOW) {
-        for (let prefToChange of prefsToChange) {
-          prefToChange.value = e10sCheckbox.checked;
-        }
-
-        Services.startup.quit(Ci.nsIAppStartup.eAttemptQuit | Ci.nsIAppStartup.eRestart);
-      }
-
-      // Revert the checkbox in case we didn't quit
-      e10sCheckbox.checked = e10sPref.value || e10sTempPref.value;
-    }
-  },
-
-  separateProfileModeChange() {
-    if (AppConstants.MOZ_DEV_EDITION) {
-      function quitApp() {
-        Services.startup.quit(Ci.nsIAppStartup.eAttemptQuit | Ci.nsIAppStartup.eRestartNotSameProfile);
-      }
-      function revertCheckbox(error) {
-        separateProfileModeCheckbox.checked = !separateProfileModeCheckbox.checked;
-        if (error) {
-          Cu.reportError("Failed to toggle separate profile mode: " + error);
-        }
-      }
-      function createOrRemoveSpecialDevEditionFile(onSuccess) {
-        let uAppData = OS.Constants.Path.userApplicationDataDir;
-        let ignoreSeparateProfile = OS.Path.join(uAppData, "ignore-dev-edition-profile");
-
-        if (separateProfileModeCheckbox.checked) {
-          OS.File.remove(ignoreSeparateProfile).then(onSuccess, revertCheckbox);
-        } else {
-          OS.File.writeAtomic(ignoreSeparateProfile, new Uint8Array()).then(onSuccess, revertCheckbox);
-        }
-      }
-
-      let separateProfileModeCheckbox = document.getElementById("separateProfileMode");
-      let button_index = confirmRestartPrompt(separateProfileModeCheckbox.checked,
-                                              0, false, true);
-      switch (button_index) {
-        case CONFIRM_RESTART_PROMPT_CANCEL:
-          revertCheckbox();
-          return;
-        case CONFIRM_RESTART_PROMPT_RESTART_NOW:
-          const Cc = Components.classes, Ci = Components.interfaces;
-          let cancelQuit = Cc["@mozilla.org/supports-PRBool;1"]
-                             .createInstance(Ci.nsISupportsPRBool);
-          Services.obs.notifyObservers(cancelQuit, "quit-application-requested",
-                                        "restart");
-          if (!cancelQuit.data) {
-            createOrRemoveSpecialDevEditionFile(quitApp);
-            return;
-          }
-
-          // Revert the checkbox in case we didn't quit
-          revertCheckbox();
-          return;
-        case CONFIRM_RESTART_PROMPT_RESTART_LATER:
-          createOrRemoveSpecialDevEditionFile();
-      }
-    }
-  },
-
-  onGetStarted(aEvent) {
-    if (AppConstants.MOZ_DEV_EDITION) {
-      const Cc = Components.classes, Ci = Components.interfaces;
-      let wm = Cc["@mozilla.org/appshell/window-mediator;1"]
-                  .getService(Ci.nsIWindowMediator);
-      let win = wm.getMostRecentWindow("navigator:browser");
-
-      fxAccounts.getSignedInUser().then(data => {
-        if (win) {
-          if (data) {
-            // We have a user, open Sync preferences in the same tab
-            win.openUILinkIn("about:preferences#sync", "current");
-            return;
-          }
-          let accountsTab = win.gBrowser.addTab("about:accounts?action=signin&entrypoint=dev-edition-setup");
-          win.gBrowser.selectedTab = accountsTab;
-        }
-      });
-    }
-  },
-
-  // HOME PAGE
-
-  /*
-   * Preferences:
-   *
-   * browser.startup.homepage
-   * - the user's home page, as a string; if the home page is a set of tabs,
-   *   this will be those URLs separated by the pipe character "|"
-   * browser.startup.page
-   * - what page(s) to show when the user starts the application, as an integer:
-   *
-   *     0: a blank page
-   *     1: the home page (as set by the browser.startup.homepage pref)
-   *     2: the last page the user visited (DEPRECATED)
-   *     3: windows and tabs from the last session (a.k.a. session restore)
-   *
-   *   The deprecated option is not exposed in UI; however, if the user has it
-   *   selected and doesn't change the UI for this preference, the deprecated
-   *   option is preserved.
-   */
-
-  syncFromHomePref() {
-    let homePref = document.getElementById("browser.startup.homepage");
-
-    // If the pref is set to about:home or about:newtab, set the value to ""
-    // to show the placeholder text (about:home title) rather than
-    // exposing those URLs to users.
-    let defaultBranch = Services.prefs.getDefaultBranch("");
-    let defaultValue = defaultBranch.getComplexValue("browser.startup.homepage",
-                                                     Ci.nsIPrefLocalizedString).data;
-    let currentValue = homePref.value.toLowerCase();
-    if (currentValue == "about:home" ||
-        (currentValue == defaultValue && currentValue == "about:newtab")) {
-      return "";
-    }
-
-    // If the pref is actually "", show about:blank.  The actual home page
-    // loading code treats them the same, and we don't want the placeholder text
-    // to be shown.
-    if (homePref.value == "")
-      return "about:blank";
-
-    // Otherwise, show the actual pref value.
-    return undefined;
-  },
-
-  syncToHomePref(value) {
-    // If the value is "", use about:home.
-    if (value == "")
-      return "about:home";
-
-    // Otherwise, use the actual textbox value.
-    return undefined;
-  },
-
-  /**
-   * Sets the home page to the current displayed page (or frontmost tab, if the
-   * most recent browser window contains multiple tabs), updating preference
-   * window UI to reflect this.
-   */
-  setHomePageToCurrent() {
-    let homePage = document.getElementById("browser.startup.homepage");
-    let tabs = this._getTabsForHomePage();
-    function getTabURI(t) {
-      return t.linkedBrowser.currentURI.spec;
-    }
-
-    // FIXME Bug 244192: using dangerous "|" joiner!
-    if (tabs.length)
-      homePage.value = tabs.map(getTabURI).join("|");
-  },
-
-  /**
-   * Displays a dialog in which the user can select a bookmark to use as home
-   * page.  If the user selects a bookmark, that bookmark's name is displayed in
-   * UI and the bookmark's address is stored to the home page preference.
-   */
-  setHomePageToBookmark() {
-    var rv = { urls: null, names: null };
-    gSubDialog.open("chrome://browser/content/preferences/selectBookmark.xul",
-                    "resizable=yes, modal=yes", rv,
-                    this._setHomePageToBookmarkClosed.bind(this, rv));
-  },
-
-  _setHomePageToBookmarkClosed(rv, aEvent) {
-    if (aEvent.detail.button != "accept")
-      return;
-    if (rv.urls && rv.names) {
-      var homePage = document.getElementById("browser.startup.homepage");
-
-      // XXX still using dangerous "|" joiner!
-      homePage.value = rv.urls.join("|");
-    }
-  },
-
-  /**
-   * Switches the "Use Current Page" button between its singular and plural
-   * forms.
-   */
-  _updateUseCurrentButton() {
-    let useCurrent = document.getElementById("useCurrent");
-
-
-    let tabs = this._getTabsForHomePage();
-
-    if (tabs.length > 1)
-      useCurrent.label = useCurrent.getAttribute("label2");
-    else
-      useCurrent.label = useCurrent.getAttribute("label1");
-
-    // In this case, the button's disabled state is set by preferences.xml.
-    let prefName = "pref.browser.homepage.disable_button.current_page";
-    if (document.getElementById(prefName).locked)
-      return;
-
-    useCurrent.disabled = !tabs.length
-  },
-
-  _getTabsForHomePage() {
-    var win;
-    var tabs = [];
-
-    const Cc = Components.classes, Ci = Components.interfaces;
-    var wm = Cc["@mozilla.org/appshell/window-mediator;1"]
-                .getService(Ci.nsIWindowMediator);
-    win = wm.getMostRecentWindow("navigator:browser");
-
-    if (win && win.document.documentElement
-                  .getAttribute("windowtype") == "navigator:browser") {
-      // We should only include visible & non-pinned tabs
-
-      tabs = win.gBrowser.visibleTabs.slice(win.gBrowser._numPinnedTabs);
-      tabs = tabs.filter(this.isNotAboutPreferences);
-    }
-
-    return tabs;
-  },
-
-  /**
-   * Check to see if a tab is not about:preferences
-   */
-  isNotAboutPreferences(aElement, aIndex, aArray) {
-    return !aElement.linkedBrowser.currentURI.spec.startsWith("about:preferences");
-  },
-
-  /**
-   * Restores the default home page as the user's home page.
-   */
-  restoreDefaultHomePage() {
-    var homePage = document.getElementById("browser.startup.homepage");
-    homePage.value = homePage.defaultValue;
-  },
-
-  /**
-   * Utility function to enable/disable the button specified by aButtonID based
-   * on the value of the Boolean preference specified by aPreferenceID.
-   */
-  updateButtons(aButtonID, aPreferenceID) {
-    var button = document.getElementById(aButtonID);
-    var preference = document.getElementById(aPreferenceID);
-    button.disabled = preference.value != true;
-    return undefined;
-  },
-
-  /**
-   * Hide/show the "Show my windows and tabs from last time" option based
-   * on the value of the browser.privatebrowsing.autostart pref.
-   */
-  updateBrowserStartupLastSession() {
-    let pbAutoStartPref = document.getElementById("browser.privatebrowsing.autostart");
-    let startupPref = document.getElementById("browser.startup.page");
-    let menu = document.getElementById("browserStartupPage");
-    let option = document.getElementById("browserStartupLastSession");
-    if (pbAutoStartPref.value) {
-      option.setAttribute("disabled", "true");
-      if (option.selected) {
-        menu.selectedItem = document.getElementById("browserStartupHomePage");
-      }
-    } else {
-      option.removeAttribute("disabled");
-      startupPref.updateElements(); // select the correct index in the startup menulist
-    }
-  },
-
-  // TABS
-
-  /*
-   * Preferences:
-   *
-   * browser.link.open_newwindow - int
-   *   Determines where links targeting new windows should open.
-   *   Values:
-   *     1 - Open in the current window or tab.
-   *     2 - Open in a new window.
-   *     3 - Open in a new tab in the most recent window.
-   * browser.tabs.loadInBackground - bool
-   *   True - Whether browser should switch to a new tab opened from a link.
-   * browser.tabs.warnOnClose - bool
-   *   True - If when closing a window with multiple tabs the user is warned and
-   *          allowed to cancel the action, false to just close the window.
-   * browser.tabs.warnOnOpen - bool
-   *   True - Whether the user should be warned when trying to open a lot of
-   *          tabs at once (e.g. a large folder of bookmarks), allowing to
-   *          cancel the action.
-   * browser.taskbar.previews.enable - bool
-   *   True - Tabs are to be shown in Windows 7 taskbar.
-   *   False - Only the window is to be shown in Windows 7 taskbar.
-   */
-
-  /**
-   * Determines where a link which opens a new window will open.
-   *
-   * @returns |true| if such links should be opened in new tabs
-   */
-  readLinkTarget() {
-    var openNewWindow = document.getElementById("browser.link.open_newwindow");
-    return openNewWindow.value != 2;
-  },
-
-  /**
-   * Determines where a link which opens a new window will open.
-   *
-   * @returns 2 if such links should be opened in new windows,
-   *          3 if such links should be opened in new tabs
-   */
-  writeLinkTarget() {
-    var linkTargeting = document.getElementById("linkTargeting");
-    return linkTargeting.checked ? 3 : 2;
-  },
-  /*
-   * Preferences:
-   *
-   * browser.shell.checkDefault
-   * - true if a default-browser check (and prompt to make it so if necessary)
-   *   occurs at startup, false otherwise
-   */
-
-  /**
-   * Show button for setting browser as default browser or information that
-   * browser is already the default browser.
-   */
-  updateSetDefaultBrowser() {
-    if (AppConstants.HAVE_SHELL_SERVICE) {
-      let shellSvc = getShellService();
-      let defaultBrowserBox = document.getElementById("defaultBrowserBox");
-      if (!shellSvc) {
-        defaultBrowserBox.hidden = true;
-        return;
-      }
-      let setDefaultPane = document.getElementById("setDefaultPane");
-      let isDefault = shellSvc.isDefaultBrowser(false, true);
-      setDefaultPane.selectedIndex = isDefault ? 1 : 0;
-      let alwaysCheck = document.getElementById("alwaysCheckDefault");
-      alwaysCheck.disabled = alwaysCheck.disabled ||
-                             isDefault && alwaysCheck.checked;
-    }
-  },
-
-  /**
-   * Set browser as the operating system default browser.
-   */
-  setDefaultBrowser() {
-    if (AppConstants.HAVE_SHELL_SERVICE) {
-      let alwaysCheckPref = document.getElementById("browser.shell.checkDefaultBrowser");
-      alwaysCheckPref.value = true;
-
-      // Reset exponential backoff delay time in order to do visual update in pollForDefaultBrowser.
-      this._backoffIndex = 0;
-
-      let shellSvc = getShellService();
-      if (!shellSvc)
-        return;
-      try {
-        shellSvc.setDefaultBrowser(true, false);
-      } catch (ex) {
-        Cu.reportError(ex);
-        return;
-      }
-
-      let selectedIndex = shellSvc.isDefaultBrowser(false, true) ? 1 : 0;
-      document.getElementById("setDefaultPane").selectedIndex = selectedIndex;
-    }
-  },
-
-  /**
-   * Shows a dialog in which the preferred language for web content may be set.
-   */
-  showLanguages() {
-    gSubDialog.open("chrome://browser/content/preferences/languages.xul");
-  },
-
-  /**
-   * Displays the translation exceptions dialog where specific site and language
-   * translation preferences can be set.
-   */
-  showTranslationExceptions() {
-    gSubDialog.open("chrome://browser/content/preferences/translation.xul");
-  },
-
-  openTranslationProviderAttribution() {
-    Components.utils.import("resource:///modules/translation/Translation.jsm");
-    Translation.openProviderAttribution();
-  },
-
-  /**
-   * Displays the fonts dialog, where web page font names and sizes can be
-   * configured.
-   */
-  configureFonts() {
-    gSubDialog.open("chrome://browser/content/preferences/fonts.xul", "resizable=no");
-  },
-
-  /**
-   * Displays the colors dialog, where default web page/link/etc. colors can be
-   * configured.
-   */
-  configureColors() {
-    gSubDialog.open("chrome://browser/content/preferences/colors.xul", "resizable=no");
-  },
-
-  // NETWORK
-  /**
-   * Displays a dialog in which proxy settings may be changed.
-   */
-  showConnections() {
-    gSubDialog.open("chrome://browser/content/preferences/connection.xul");
-  },
-
-  checkBrowserContainers(event) {
-    let checkbox = document.getElementById("browserContainersCheckbox");
-    if (checkbox.checked) {
-      Services.prefs.setBoolPref("privacy.userContext.enabled", true);
-      return;
-    }
-
-    let count = ContextualIdentityService.countContainerTabs();
-    if (count == 0) {
-      Services.prefs.setBoolPref("privacy.userContext.enabled", false);
-      return;
-    }
-
-    let bundlePreferences = document.getElementById("bundlePreferences");
-
-    let title = bundlePreferences.getString("disableContainersAlertTitle");
-    let message = PluralForm.get(count, bundlePreferences.getString("disableContainersMsg"))
-                            .replace("#S", count)
-    let okButton = PluralForm.get(count, bundlePreferences.getString("disableContainersOkButton"))
-                             .replace("#S", count)
-    let cancelButton = bundlePreferences.getString("disableContainersButton2");
-
-    let buttonFlags = (Ci.nsIPrompt.BUTTON_TITLE_IS_STRING * Ci.nsIPrompt.BUTTON_POS_0) +
-                      (Ci.nsIPrompt.BUTTON_TITLE_IS_STRING * Ci.nsIPrompt.BUTTON_POS_1);
-
-    let rv = Services.prompt.confirmEx(window, title, message, buttonFlags,
-                                       okButton, cancelButton, null, null, {});
-    if (rv == 0) {
-      Services.prefs.setBoolPref("privacy.userContext.enabled", false);
-      return;
-    }
-
-    checkbox.checked = true;
-  },
-
-  /**
-   * Displays container panel for customising and adding containers.
-   */
-  showContainerSettings() {
-    gotoPref("containers");
-  },
-
-  /**
-   * ui.osk.enabled
-   * - when set to true, subject to other conditions, we may sometimes invoke
-   *   an on-screen keyboard when a text input is focused.
-   *   (Currently Windows-only, and depending on prefs, may be Windows-8-only)
-   */
-  updateOnScreenKeyboardVisibility() {
-    if (AppConstants.platform == "win") {
-      let minVersion = Services.prefs.getBoolPref("ui.osk.require_win10") ? 10 : 6.2;
-      if (Services.vc.compare(Services.sysinfo.getProperty("version"), minVersion) >= 0) {
-        document.getElementById("useOnScreenKeyboard").hidden = false;
-      }
-    }
-  },
-
-  updateHardwareAcceleration() {
-    // Placeholder for restart on change
-  },
-
-  // FONTS
-
-  /**
-   * Populates the default font list in UI.
-   */
-  _rebuildFonts() {
-    var preferences = document.getElementById("mainPreferences");
-    // Ensure preferences are "visible" to ensure bindings work.
-    preferences.hidden = false;
-    // Force flush:
-    preferences.clientHeight;
-    var langGroupPref = document.getElementById("font.language.group");
-    this._selectDefaultLanguageGroup(langGroupPref.value,
-                                     this._readDefaultFontTypeForLanguage(langGroupPref.value) == "serif");
-  },
-
-  /**
-   * Returns the type of the current default font for the language denoted by
-   * aLanguageGroup.
-   */
-  _readDefaultFontTypeForLanguage(aLanguageGroup) {
-    const kDefaultFontType = "font.default.%LANG%";
-    var defaultFontTypePref = kDefaultFontType.replace(/%LANG%/, aLanguageGroup);
-    var preference = document.getElementById(defaultFontTypePref);
-    if (!preference) {
-      preference = document.createElement("preference");
-      preference.id = defaultFontTypePref;
-      preference.setAttribute("name", defaultFontTypePref);
-      preference.setAttribute("type", "string");
-      preference.setAttribute("onchange", "gMainPane._rebuildFonts();");
-      document.getElementById("mainPreferences").appendChild(preference);
-    }
-    return preference.value;
-  },
-
-  _selectDefaultLanguageGroup(aLanguageGroup, aIsSerif) {
-    const kFontNameFmtSerif         = "font.name.serif.%LANG%";
-    const kFontNameFmtSansSerif     = "font.name.sans-serif.%LANG%";
-    const kFontNameListFmtSerif     = "font.name-list.serif.%LANG%";
-    const kFontNameListFmtSansSerif = "font.name-list.sans-serif.%LANG%";
-    const kFontSizeFmtVariable      = "font.size.variable.%LANG%";
-
-    var preferences = document.getElementById("mainPreferences");
-    var prefs = [{ format: aIsSerif ? kFontNameFmtSerif : kFontNameFmtSansSerif,
-                   type: "fontname",
-                   element: "defaultFont",
-                   fonttype: aIsSerif ? "serif" : "sans-serif" },
-                 { format: aIsSerif ? kFontNameListFmtSerif : kFontNameListFmtSansSerif,
-                   type: "unichar",
-                   element: null,
-                   fonttype: aIsSerif ? "serif" : "sans-serif" },
-                 { format: kFontSizeFmtVariable,
-                   type: "int",
-                   element: "defaultFontSize",
-                   fonttype: null }];
-    for (var i = 0; i < prefs.length; ++i) {
-      var preference = document.getElementById(prefs[i].format.replace(/%LANG%/, aLanguageGroup));
-      if (!preference) {
-        preference = document.createElement("preference");
-        var name = prefs[i].format.replace(/%LANG%/, aLanguageGroup);
-        preference.id = name;
-        preference.setAttribute("name", name);
-        preference.setAttribute("type", prefs[i].type);
-        preferences.appendChild(preference);
-      }
-
-      if (!prefs[i].element)
-        continue;
-
-      var element = document.getElementById(prefs[i].element);
-      if (element) {
-        element.setAttribute("preference", preference.id);
-
-        if (prefs[i].fonttype)
-          FontBuilder.buildFontList(aLanguageGroup, prefs[i].fonttype, element);
-
-        preference.setElementValue(element);
-      }
-    }
-  },
-
-  /**
-   * Stores the original value of the spellchecking preference to enable proper
-   * restoration if unchanged (since we're mapping a tristate onto a checkbox).
-   */
-  _storedSpellCheck: 0,
-
-  /**
-   * Returns true if any spellchecking is enabled and false otherwise, caching
-   * the current value to enable proper pref restoration if the checkbox is
-   * never changed.
-   *
-   * layout.spellcheckDefault
-   * - an integer:
-   *     0  disables spellchecking
-   *     1  enables spellchecking, but only for multiline text fields
-   *     2  enables spellchecking for all text fields
-   */
-  readCheckSpelling() {
-    var pref = document.getElementById("layout.spellcheckDefault");
-    this._storedSpellCheck = pref.value;
-
-    return (pref.value != 0);
-  },
-
-  /**
-   * Returns the value of the spellchecking preference represented by UI,
-   * preserving the preference's "hidden" value if the preference is
-   * unchanged and represents a value not strictly allowed in UI.
-   */
-  writeCheckSpelling() {
-    var checkbox = document.getElementById("checkSpelling");
-    if (checkbox.checked) {
-      if (this._storedSpellCheck == 2) {
-        return 2;
-      }
-      return 1;
-    }
-    return 0;
-  },
-
-  updateDefaultPerformanceSettingsPref() {
-    let defaultPerformancePref =
-      document.getElementById("browser.preferences.defaultPerformanceSettings.enabled");
-    let processCountPref = document.getElementById("dom.ipc.processCount");
-    let accelerationPref = document.getElementById("layers.acceleration.disabled");
-    if (processCountPref.value != processCountPref.defaultValue ||
-        accelerationPref.value != accelerationPref.defaultValue) {
-      defaultPerformancePref.value = false;
-    }
-  },
-
-  updatePerformanceSettingsBox({duringChangeEvent}) {
-    let defaultPerformancePref =
-      document.getElementById("browser.preferences.defaultPerformanceSettings.enabled");
-    let performanceSettings = document.getElementById("performanceSettings");
-    let processCountPref = document.getElementById("dom.ipc.processCount");
-    if (defaultPerformancePref.value) {
-      let accelerationPref = document.getElementById("layers.acceleration.disabled");
-      // Unset the value so process count will be decided by e10s rollout.
-      processCountPref.value = processCountPref.defaultValue;
-      accelerationPref.value = accelerationPref.defaultValue;
-      performanceSettings.hidden = true;
-    } else {
-      let e10sRolloutProcessCountPref =
-        document.getElementById("dom.ipc.processCount.web");
-      // Take the e10s rollout value as the default value (if it exists),
-      // but don't overwrite the user set value.
-      if (duringChangeEvent &&
-          e10sRolloutProcessCountPref.value &&
-          processCountPref.value == processCountPref.defaultValue) {
-        processCountPref.value = e10sRolloutProcessCountPref.value;
-      }
-      performanceSettings.hidden = false;
-    }
-  },
-
-  buildContentProcessCountMenuList() {
-    if (gMainPane.isE10SEnabled()) {
-      let processCountPref = document.getElementById("dom.ipc.processCount");
-      let e10sRolloutProcessCountPref =
-        document.getElementById("dom.ipc.processCount.web");
-      let defaultProcessCount =
-        e10sRolloutProcessCountPref.value || processCountPref.defaultValue;
-      let bundlePreferences = document.getElementById("bundlePreferences");
-      let label = bundlePreferences.getFormattedString("defaultContentProcessCount",
-        [defaultProcessCount]);
-      let contentProcessCount =
-        document.querySelector(`#contentProcessCount > menupopup >
-                                menuitem[value="${defaultProcessCount}"]`);
-      contentProcessCount.label = label;
-
-      document.getElementById("limitContentProcess").disabled = false;
-      document.getElementById("contentProcessCount").disabled = false;
-      document.getElementById("contentProcessCountEnabledDescription").hidden = false;
-      document.getElementById("contentProcessCountDisabledDescription").hidden = true;
-    } else {
-      document.getElementById("limitContentProcess").disabled = true;
-      document.getElementById("contentProcessCount").disabled = true;
-      document.getElementById("contentProcessCountEnabledDescription").hidden = true;
-      document.getElementById("contentProcessCountDisabledDescription").hidden = false;
-    }
-  },
-
-  /*
-   * Preferences:
-   *
-   * app.update.enabled
-   * - true if updates to the application are enabled, false otherwise
-   * app.update.auto
-   * - true if updates should be automatically downloaded and installed and
-   * false if the user should be asked what he wants to do when an update is
-   * available
-   * extensions.update.enabled
-   * - true if updates to extensions and themes are enabled, false otherwise
-   * browser.search.update
-   * - true if updates to search engines are enabled, false otherwise
-   */
-
-  /**
-   * Selects the item of the radiogroup based on the pref values and locked
-   * states.
-   *
-   * UI state matrix for update preference conditions
-   *
-   * UI Components:                              Preferences
-   * Radiogroup                                  i   = app.update.enabled
-   *                                             ii  = app.update.auto
-   *
-   * Disabled states:
-   * Element           pref  value  locked  disabled
-   * radiogroup        i     t/f    f       false
-   *                   i     t/f    *t*     *true*
-   *                   ii    t/f    f       false
-   *                   ii    t/f    *t*     *true*
-   */
-  updateReadPrefs() {
-    if (AppConstants.MOZ_UPDATER) {
-      var enabledPref = document.getElementById("app.update.enabled");
-      var autoPref = document.getElementById("app.update.auto");
-      var radiogroup = document.getElementById("updateRadioGroup");
-
-      if (!enabledPref.value)   // Don't care for autoPref.value in this case.
-        radiogroup.value = "manual";    // 3. Never check for updates.
-      else if (autoPref.value)  // enabledPref.value && autoPref.value
-        radiogroup.value = "auto";      // 1. Automatically install updates
-      else                      // enabledPref.value && !autoPref.value
-        radiogroup.value = "checkOnly"; // 2. Check, but let me choose
-
-      var canCheck = Components.classes["@mozilla.org/updates/update-service;1"].
-                       getService(Components.interfaces.nsIApplicationUpdateService).
-                       canCheckForUpdates;
-      // canCheck is false if the enabledPref is false and locked,
-      // or the binary platform or OS version is not known.
-      // A locked pref is sufficient to disable the radiogroup.
-      radiogroup.disabled = !canCheck || enabledPref.locked || autoPref.locked;
-
-      if (AppConstants.MOZ_MAINTENANCE_SERVICE) {
-        // Check to see if the maintenance service is installed.
-        // If it is don't show the preference at all.
-        var installed;
-        try {
-          var wrk = Components.classes["@mozilla.org/windows-registry-key;1"]
-                    .createInstance(Components.interfaces.nsIWindowsRegKey);
-          wrk.open(wrk.ROOT_KEY_LOCAL_MACHINE,
-                   "SOFTWARE\\Mozilla\\MaintenanceService",
-                   wrk.ACCESS_READ | wrk.WOW64_64);
-          installed = wrk.readIntValue("Installed");
-          wrk.close();
-        } catch (e) {
-        }
-        if (installed != 1) {
-          document.getElementById("useService").hidden = true;
-        }
-      }
-    }
-  },
-
-  /**
-   * Sets the pref values based on the selected item of the radiogroup.
-   */
-  updateWritePrefs() {
-    if (AppConstants.MOZ_UPDATER) {
-      var enabledPref = document.getElementById("app.update.enabled");
-      var autoPref = document.getElementById("app.update.auto");
-      var radiogroup = document.getElementById("updateRadioGroup");
-      switch (radiogroup.value) {
-        case "auto":      // 1. Automatically install updates for Desktop only
-          enabledPref.value = true;
-          autoPref.value = true;
-          break;
-        case "checkOnly": // 2. Check, but let me choose
-          enabledPref.value = true;
-          autoPref.value = false;
-          break;
-        case "manual":    // 3. Never check for updates.
-          enabledPref.value = false;
-          autoPref.value = false;
-      }
-    }
-  },
-
-  /**
-   * Displays the history of installed updates.
-   */
-  showUpdates() {
-    gSubDialog.open("chrome://mozapps/content/update/history.xul");
-  },
-
-  destroy() {
-    window.removeEventListener("unload", this);
-    this._prefSvc.removeObserver(PREF_SHOW_PLUGINS_IN_LIST, this);
-    this._prefSvc.removeObserver(PREF_HIDE_PLUGINS_WITHOUT_EXTENSIONS, this);
-    this._prefSvc.removeObserver(PREF_FEED_SELECTED_APP, this);
-    this._prefSvc.removeObserver(PREF_FEED_SELECTED_WEB, this);
-    this._prefSvc.removeObserver(PREF_FEED_SELECTED_ACTION, this);
-    this._prefSvc.removeObserver(PREF_FEED_SELECTED_READER, this);
-
-    this._prefSvc.removeObserver(PREF_VIDEO_FEED_SELECTED_APP, this);
-    this._prefSvc.removeObserver(PREF_VIDEO_FEED_SELECTED_WEB, this);
-    this._prefSvc.removeObserver(PREF_VIDEO_FEED_SELECTED_ACTION, this);
-    this._prefSvc.removeObserver(PREF_VIDEO_FEED_SELECTED_READER, this);
-
-    this._prefSvc.removeObserver(PREF_AUDIO_FEED_SELECTED_APP, this);
-    this._prefSvc.removeObserver(PREF_AUDIO_FEED_SELECTED_WEB, this);
-    this._prefSvc.removeObserver(PREF_AUDIO_FEED_SELECTED_ACTION, this);
-    this._prefSvc.removeObserver(PREF_AUDIO_FEED_SELECTED_READER, this);
-  },
-
-
-  // nsISupports
-
-  QueryInterface(aIID) {
-    if (aIID.equals(Ci.nsIObserver) ||
-        aIID.equals(Ci.nsIDOMEventListener ||
-        aIID.equals(Ci.nsISupports)))
-      return this;
-
-    throw Cr.NS_ERROR_NO_INTERFACE;
-  },
-
-
-  // nsIObserver
-
-  observe(aSubject, aTopic, aData) {
-    if (aTopic == "nsPref:changed") {
-      // Rebuild the list when there are changes to preferences that influence
-      // whether or not to show certain entries in the list.
-      if (!this._storingAction) {
-        // These two prefs alter the list of visible types, so we have to rebuild
-        // that list when they change.
-        if (aData == PREF_SHOW_PLUGINS_IN_LIST ||
-            aData == PREF_HIDE_PLUGINS_WITHOUT_EXTENSIONS) {
-          this._rebuildVisibleTypes();
-          this._sortVisibleTypes();
-        }
-
-        // All the prefs we observe can affect what we display, so we rebuild
-        // the view when any of them changes.
-        this._rebuildView();
-      }
-      if (AppConstants.MOZ_UPDATER) {
-        this.updateReadPrefs();
-      }
-    }
-  },
-
-
-  // nsIDOMEventListener
-
-  handleEvent(aEvent) {
-    if (aEvent.type == "unload") {
-      this.destroy();
-    }
-  },
-
-
-  // Composed Model Construction
-
-  _loadData() {
-    this._loadFeedHandler();
-    this._loadInternalHandlers();
-    this._loadPluginHandlers();
-    this._loadApplicationHandlers();
-  },
-
-  _loadFeedHandler() {
-    this._handledTypes[TYPE_MAYBE_FEED] = feedHandlerInfo;
-    feedHandlerInfo.handledOnlyByPlugin = false;
-
-    this._handledTypes[TYPE_MAYBE_VIDEO_FEED] = videoFeedHandlerInfo;
-    videoFeedHandlerInfo.handledOnlyByPlugin = false;
-
-    this._handledTypes[TYPE_MAYBE_AUDIO_FEED] = audioFeedHandlerInfo;
-    audioFeedHandlerInfo.handledOnlyByPlugin = false;
-  },
-
-  /**
-   * Load higher level internal handlers so they can be turned on/off in the
-   * applications menu.
-   */
-  _loadInternalHandlers() {
-    var internalHandlers = [pdfHandlerInfo];
-    for (let internalHandler of internalHandlers) {
-      if (internalHandler.enabled) {
-        this._handledTypes[internalHandler.type] = internalHandler;
-      }
-    }
-  },
-
-  /**
-   * Load the set of handlers defined by plugins.
-   *
-   * Note: if there's more than one plugin for a given MIME type, we assume
-   * the last one is the one that the application will use.  That may not be
-   * correct, but it's how we've been doing it for years.
-   *
-   * Perhaps we should instead query navigator.mimeTypes for the set of types
-   * supported by the application and then get the plugin from each MIME type's
-   * enabledPlugin property.  But if there's a plugin for a type, we need
-   * to know about it even if it isn't enabled, since we're going to give
-   * the user an option to enable it.
-   *
-   * Also note that enabledPlugin does not get updated when
-   * plugin.disable_full_page_plugin_for_types changes, so even if we could use
-   * enabledPlugin to get the plugin that would be used, we'd still need to
-   * check the pref ourselves to find out if it's enabled.
-   */
-  _loadPluginHandlers() {
-    "use strict";
-
-    let mimeTypes = navigator.mimeTypes;
-
-    for (let mimeType of mimeTypes) {
-      let handlerInfoWrapper;
-      if (mimeType.type in this._handledTypes) {
-        handlerInfoWrapper = this._handledTypes[mimeType.type];
-      } else {
-        let wrappedHandlerInfo =
-              this._mimeSvc.getFromTypeAndExtension(mimeType.type, null);
-        handlerInfoWrapper = new HandlerInfoWrapper(mimeType.type, wrappedHandlerInfo);
-        handlerInfoWrapper.handledOnlyByPlugin = true;
-        this._handledTypes[mimeType.type] = handlerInfoWrapper;
-      }
-      handlerInfoWrapper.pluginName = mimeType.enabledPlugin.name;
-    }
-  },
-
-  /**
-   * Load the set of handlers defined by the application datastore.
-   */
-  _loadApplicationHandlers() {
-    var wrappedHandlerInfos = this._handlerSvc.enumerate();
-    while (wrappedHandlerInfos.hasMoreElements()) {
-      let wrappedHandlerInfo =
-        wrappedHandlerInfos.getNext().QueryInterface(Ci.nsIHandlerInfo);
-      let type = wrappedHandlerInfo.type;
-
-      let handlerInfoWrapper;
-      if (type in this._handledTypes)
-        handlerInfoWrapper = this._handledTypes[type];
-      else {
-        handlerInfoWrapper = new HandlerInfoWrapper(type, wrappedHandlerInfo);
-        this._handledTypes[type] = handlerInfoWrapper;
-      }
-
-      handlerInfoWrapper.handledOnlyByPlugin = false;
-    }
-  },
-
-
-  // View Construction
-
-  _rebuildVisibleTypes() {
-    // Reset the list of visible types and the visible type description counts.
-    this._visibleTypes = [];
-    this._visibleTypeDescriptionCount = {};
-
-    // Get the preferences that help determine what types to show.
-    var showPlugins = this._prefSvc.getBoolPref(PREF_SHOW_PLUGINS_IN_LIST);
-    var hidePluginsWithoutExtensions =
-      this._prefSvc.getBoolPref(PREF_HIDE_PLUGINS_WITHOUT_EXTENSIONS);
-
-    for (let type in this._handledTypes) {
-      let handlerInfo = this._handledTypes[type];
-
-      // Hide plugins without associated extensions if so prefed so we don't
-      // show a whole bunch of obscure types handled by plugins on Mac.
-      // Note: though protocol types don't have extensions, we still show them;
-      // the pref is only meant to be applied to MIME types, since plugins are
-      // only associated with MIME types.
-      // FIXME: should we also check the "suffixes" property of the plugin?
-      // Filed as bug 395135.
-      if (hidePluginsWithoutExtensions && handlerInfo.handledOnlyByPlugin &&
-          handlerInfo.wrappedHandlerInfo instanceof Ci.nsIMIMEInfo &&
-          !handlerInfo.primaryExtension)
-        continue;
-
-      // Hide types handled only by plugins if so prefed.
-      if (handlerInfo.handledOnlyByPlugin && !showPlugins)
-        continue;
-
-      // We couldn't find any reason to exclude the type, so include it.
-      this._visibleTypes.push(handlerInfo);
-
-      if (handlerInfo.description in this._visibleTypeDescriptionCount)
-        this._visibleTypeDescriptionCount[handlerInfo.description]++;
-      else
-        this._visibleTypeDescriptionCount[handlerInfo.description] = 1;
-    }
-  },
-
-  _rebuildView() {
-    // Clear the list of entries.
-    while (this._list.childNodes.length > 1)
-      this._list.removeChild(this._list.lastChild);
-
-    var visibleTypes = this._visibleTypes;
-
-    // If the user is filtering the list, then only show matching types.
-    if (this._filter.value)
-      visibleTypes = visibleTypes.filter(this._matchesFilter, this);
-
-    for (let visibleType of visibleTypes) {
-      let item = document.createElement("richlistitem");
-      item.setAttribute("type", visibleType.type);
-      item.setAttribute("typeDescription", this._describeType(visibleType));
-      if (visibleType.smallIcon)
-        item.setAttribute("typeIcon", visibleType.smallIcon);
-      item.setAttribute("actionDescription",
-                        this._describePreferredAction(visibleType));
-
-      if (!this._setIconClassForPreferredAction(visibleType, item)) {
-        item.setAttribute("actionIcon",
-                          this._getIconURLForPreferredAction(visibleType));
-      }
-
-      this._list.appendChild(item);
-    }
-
-    this._selectLastSelectedType();
-  },
-
-  _matchesFilter(aType) {
-    var filterValue = this._filter.value.toLowerCase();
-    return this._describeType(aType).toLowerCase().indexOf(filterValue) != -1 ||
-           this._describePreferredAction(aType).toLowerCase().indexOf(filterValue) != -1;
-  },
-
-  /**
-   * Describe, in a human-readable fashion, the type represented by the given
-   * handler info object.  Normally this is just the description provided by
-   * the info object, but if more than one object presents the same description,
-   * then we annotate the duplicate descriptions with the type itself to help
-   * users distinguish between those types.
-   *
-   * @param aHandlerInfo {nsIHandlerInfo} the type being described
-   * @returns {string} a description of the type
-   */
-  _describeType(aHandlerInfo) {
-    if (this._visibleTypeDescriptionCount[aHandlerInfo.description] > 1)
-      return this._prefsBundle.getFormattedString("typeDescriptionWithType",
-                                                  [aHandlerInfo.description,
-                                                   aHandlerInfo.type]);
-
-    return aHandlerInfo.description;
-  },
-
-  /**
-   * Describe, in a human-readable fashion, the preferred action to take on
-   * the type represented by the given handler info object.
-   *
-   * XXX Should this be part of the HandlerInfoWrapper interface?  It would
-   * violate the separation of model and view, but it might make more sense
-   * nonetheless (f.e. it would make sortTypes easier).
-   *
-   * @param aHandlerInfo {nsIHandlerInfo} the type whose preferred action
-   *                                      is being described
-   * @returns {string} a description of the action
-   */
-  _describePreferredAction(aHandlerInfo) {
-    // alwaysAskBeforeHandling overrides the preferred action, so if that flag
-    // is set, then describe that behavior instead.  For most types, this is
-    // the "alwaysAsk" string, but for the feed type we show something special.
-    if (aHandlerInfo.alwaysAskBeforeHandling) {
-      if (isFeedType(aHandlerInfo.type))
-        return this._prefsBundle.getFormattedString("previewInApp",
-                                                    [this._brandShortName]);
-      return this._prefsBundle.getString("alwaysAsk");
-    }
-
-    switch (aHandlerInfo.preferredAction) {
-      case Ci.nsIHandlerInfo.saveToDisk:
-        return this._prefsBundle.getString("saveFile");
-
-      case Ci.nsIHandlerInfo.useHelperApp:
-        var preferredApp = aHandlerInfo.preferredApplicationHandler;
-        var name;
-        if (preferredApp instanceof Ci.nsILocalHandlerApp)
-          name = getFileDisplayName(preferredApp.executable);
-        else
-          name = preferredApp.name;
-        return this._prefsBundle.getFormattedString("useApp", [name]);
-
-      case Ci.nsIHandlerInfo.handleInternally:
-        // For the feed type, handleInternally means live bookmarks.
-        if (isFeedType(aHandlerInfo.type)) {
-          return this._prefsBundle.getFormattedString("addLiveBookmarksInApp",
-                                                      [this._brandShortName]);
-        }
-
-        if (aHandlerInfo instanceof InternalHandlerInfoWrapper) {
-          return this._prefsBundle.getFormattedString("previewInApp",
-                                                      [this._brandShortName]);
-        }
-
-        // For other types, handleInternally looks like either useHelperApp
-        // or useSystemDefault depending on whether or not there's a preferred
-        // handler app.
-        if (this.isValidHandlerApp(aHandlerInfo.preferredApplicationHandler))
-          return aHandlerInfo.preferredApplicationHandler.name;
-
-        return aHandlerInfo.defaultDescription;
-
-        // XXX Why don't we say the app will handle the type internally?
-        // Is it because the app can't actually do that?  But if that's true,
-        // then why would a preferredAction ever get set to this value
-        // in the first place?
-
-      case Ci.nsIHandlerInfo.useSystemDefault:
-        return this._prefsBundle.getFormattedString("useDefault",
-                                                    [aHandlerInfo.defaultDescription]);
-
-      case kActionUsePlugin:
-        return this._prefsBundle.getFormattedString("usePluginIn",
-                                                    [aHandlerInfo.pluginName,
-                                                     this._brandShortName]);
-      default:
-        throw new Error(`Unexpected preferredAction: ${aHandlerInfo.preferredAction}`);
-    }
-  },
-
-  _selectLastSelectedType() {
-    // If the list is disabled by the pref.downloads.disable_button.edit_actions
-    // preference being locked, then don't select the type, as that would cause
-    // it to appear selected, with a different background and an actions menu
-    // that makes it seem like you can choose an action for the type.
-    if (this._list.disabled)
-      return;
-
-    var lastSelectedType = this._list.getAttribute("lastSelectedType");
-    if (!lastSelectedType)
-      return;
-
-    var item = this._list.getElementsByAttribute("type", lastSelectedType)[0];
-    if (!item)
-      return;
-
-    this._list.selectedItem = item;
-  },
-
-  /**
-   * Whether or not the given handler app is valid.
-   *
-   * @param aHandlerApp {nsIHandlerApp} the handler app in question
-   *
-   * @returns {boolean} whether or not it's valid
-   */
-  isValidHandlerApp(aHandlerApp) {
-    if (!aHandlerApp)
-      return false;
-
-    if (aHandlerApp instanceof Ci.nsILocalHandlerApp)
-      return this._isValidHandlerExecutable(aHandlerApp.executable);
-
-    if (aHandlerApp instanceof Ci.nsIWebHandlerApp)
-      return aHandlerApp.uriTemplate;
-
-    if (aHandlerApp instanceof Ci.nsIWebContentHandlerInfo)
-      return aHandlerApp.uri;
-
-    return false;
-  },
-
-  _isValidHandlerExecutable(aExecutable) {
-    let leafName;
-    if (AppConstants.platform == "win") {
-      leafName = `${AppConstants.MOZ_APP_NAME}.exe`;
-    } else if (AppConstants.platform == "macosx") {
-      leafName = AppConstants.MOZ_MACBUNDLE_NAME;
-    } else {
-      leafName = `${AppConstants.MOZ_APP_NAME}-bin`;
-    }
-    return aExecutable &&
-           aExecutable.exists() &&
-           aExecutable.isExecutable() &&
-// XXXben - we need to compare this with the running instance executable
-//          just don't know how to do that via script...
-// XXXmano TBD: can probably add this to nsIShellService
-           aExecutable.leafName != leafName;
-  },
-
-  /**
-   * Rebuild the actions menu for the selected entry.  Gets called by
-   * the richlistitem constructor when an entry in the list gets selected.
-   */
-  rebuildActionsMenu() {
-    var typeItem = this._list.selectedItem;
-    var handlerInfo = this._handledTypes[typeItem.type];
-    var menu =
-      document.getAnonymousElementByAttribute(typeItem, "class", "actionsMenu");
-    var menuPopup = menu.menupopup;
-
-    // Clear out existing items.
-    while (menuPopup.hasChildNodes())
-      menuPopup.removeChild(menuPopup.lastChild);
-
-    let internalMenuItem;
-    // Add the "Preview in Firefox" option for optional internal handlers.
-    if (handlerInfo instanceof InternalHandlerInfoWrapper) {
-      internalMenuItem = document.createElement("menuitem");
-      internalMenuItem.setAttribute("action", Ci.nsIHandlerInfo.handleInternally);
-      let label = this._prefsBundle.getFormattedString("previewInApp",
-                                                       [this._brandShortName]);
-      internalMenuItem.setAttribute("label", label);
-      internalMenuItem.setAttribute("tooltiptext", label);
-      internalMenuItem.setAttribute(APP_ICON_ATTR_NAME, "ask");
-      menuPopup.appendChild(internalMenuItem);
-    }
-
-    {
-      var askMenuItem = document.createElement("menuitem");
-      askMenuItem.setAttribute("action", Ci.nsIHandlerInfo.alwaysAsk);
-      let label;
-      if (isFeedType(handlerInfo.type))
-        label = this._prefsBundle.getFormattedString("previewInApp",
-                                                     [this._brandShortName]);
-      else
-        label = this._prefsBundle.getString("alwaysAsk");
-      askMenuItem.setAttribute("label", label);
-      askMenuItem.setAttribute("tooltiptext", label);
-      askMenuItem.setAttribute(APP_ICON_ATTR_NAME, "ask");
-      menuPopup.appendChild(askMenuItem);
-    }
-
-    // Create a menu item for saving to disk.
-    // Note: this option isn't available to protocol types, since we don't know
-    // what it means to save a URL having a certain scheme to disk, nor is it
-    // available to feeds, since the feed code doesn't implement the capability.
-    if ((handlerInfo.wrappedHandlerInfo instanceof Ci.nsIMIMEInfo) &&
-        !isFeedType(handlerInfo.type)) {
-      var saveMenuItem = document.createElement("menuitem");
-      saveMenuItem.setAttribute("action", Ci.nsIHandlerInfo.saveToDisk);
-      let label = this._prefsBundle.getString("saveFile");
-      saveMenuItem.setAttribute("label", label);
-      saveMenuItem.setAttribute("tooltiptext", label);
-      saveMenuItem.setAttribute(APP_ICON_ATTR_NAME, "save");
-      menuPopup.appendChild(saveMenuItem);
-    }
-
-    // If this is the feed type, add a Live Bookmarks item.
-    if (isFeedType(handlerInfo.type)) {
-      internalMenuItem = document.createElement("menuitem");
-      internalMenuItem.setAttribute("action", Ci.nsIHandlerInfo.handleInternally);
-      let label = this._prefsBundle.getFormattedString("addLiveBookmarksInApp",
-                                                       [this._brandShortName]);
-      internalMenuItem.setAttribute("label", label);
-      internalMenuItem.setAttribute("tooltiptext", label);
-      internalMenuItem.setAttribute(APP_ICON_ATTR_NAME, "feed");
-      menuPopup.appendChild(internalMenuItem);
-    }
-
-    // Add a separator to distinguish these items from the helper app items
-    // that follow them.
-    let menuseparator = document.createElement("menuseparator");
-    menuPopup.appendChild(menuseparator);
-
-    // Create a menu item for the OS default application, if any.
-    if (handlerInfo.hasDefaultHandler) {
-      var defaultMenuItem = document.createElement("menuitem");
-      defaultMenuItem.setAttribute("action", Ci.nsIHandlerInfo.useSystemDefault);
-      let label = this._prefsBundle.getFormattedString("useDefault",
-                                                       [handlerInfo.defaultDescription]);
-      defaultMenuItem.setAttribute("label", label);
-      defaultMenuItem.setAttribute("tooltiptext", handlerInfo.defaultDescription);
-      defaultMenuItem.setAttribute("image", this._getIconURLForSystemDefault(handlerInfo));
-
-      menuPopup.appendChild(defaultMenuItem);
-    }
-
-    // Create menu items for possible handlers.
-    let preferredApp = handlerInfo.preferredApplicationHandler;
-    let possibleApps = handlerInfo.possibleApplicationHandlers.enumerate();
-    var possibleAppMenuItems = [];
-    while (possibleApps.hasMoreElements()) {
-      let possibleApp = possibleApps.getNext();
-      if (!this.isValidHandlerApp(possibleApp))
-        continue;
-
-      let menuItem = document.createElement("menuitem");
-      menuItem.setAttribute("action", Ci.nsIHandlerInfo.useHelperApp);
-      let label;
-      if (possibleApp instanceof Ci.nsILocalHandlerApp)
-        label = getFileDisplayName(possibleApp.executable);
-      else
-        label = possibleApp.name;
-      label = this._prefsBundle.getFormattedString("useApp", [label]);
-      menuItem.setAttribute("label", label);
-      menuItem.setAttribute("tooltiptext", label);
-      menuItem.setAttribute("image", this._getIconURLForHandlerApp(possibleApp));
-
-      // Attach the handler app object to the menu item so we can use it
-      // to make changes to the datastore when the user selects the item.
-      menuItem.handlerApp = possibleApp;
-
-      menuPopup.appendChild(menuItem);
-      possibleAppMenuItems.push(menuItem);
-    }
-
-    // Create a menu item for the plugin.
-    if (handlerInfo.pluginName) {
-      var pluginMenuItem = document.createElement("menuitem");
-      pluginMenuItem.setAttribute("action", kActionUsePlugin);
-      let label = this._prefsBundle.getFormattedString("usePluginIn",
-                                                       [handlerInfo.pluginName,
-                                                        this._brandShortName]);
-      pluginMenuItem.setAttribute("label", label);
-      pluginMenuItem.setAttribute("tooltiptext", label);
-      pluginMenuItem.setAttribute(APP_ICON_ATTR_NAME, "plugin");
-      menuPopup.appendChild(pluginMenuItem);
-    }
-
-    // Create a menu item for selecting a local application.
-    let canOpenWithOtherApp = true;
-    if (AppConstants.platform == "win") {
-      // On Windows, selecting an application to open another application
-      // would be meaningless so we special case executables.
-      let executableType = Cc["@mozilla.org/mime;1"].getService(Ci.nsIMIMEService)
-                                                    .getTypeFromExtension("exe");
-      canOpenWithOtherApp = handlerInfo.type != executableType;
-    }
-    if (canOpenWithOtherApp) {
-      let menuItem = document.createElement("menuitem");
-      menuItem.className = "choose-app-item";
-      menuItem.addEventListener("command", function(e) {
-        gMainPane.chooseApp(e);
-      });
-      let label = this._prefsBundle.getString("useOtherApp");
-      menuItem.setAttribute("label", label);
-      menuItem.setAttribute("tooltiptext", label);
-      menuPopup.appendChild(menuItem);
-    }
-
-    // Create a menu item for managing applications.
-    if (possibleAppMenuItems.length) {
-      let menuItem = document.createElement("menuseparator");
-      menuPopup.appendChild(menuItem);
-      menuItem = document.createElement("menuitem");
-      menuItem.className = "manage-app-item";
-      menuItem.addEventListener("command", function(e) {
-        gMainPane.manageApp(e);
-      });
-      menuItem.setAttribute("label", this._prefsBundle.getString("manageApp"));
-      menuPopup.appendChild(menuItem);
-    }
-
-    // Select the item corresponding to the preferred action.  If the always
-    // ask flag is set, it overrides the preferred action.  Otherwise we pick
-    // the item identified by the preferred action (when the preferred action
-    // is to use a helper app, we have to pick the specific helper app item).
-    if (handlerInfo.alwaysAskBeforeHandling)
-      menu.selectedItem = askMenuItem;
-    else switch (handlerInfo.preferredAction) {
-      case Ci.nsIHandlerInfo.handleInternally:
-        if (internalMenuItem) {
-          menu.selectedItem = internalMenuItem;
-        } else {
-          Cu.reportError("No menu item defined to set!")
-        }
-        break;
-      case Ci.nsIHandlerInfo.useSystemDefault:
-        menu.selectedItem = defaultMenuItem;
-        break;
-      case Ci.nsIHandlerInfo.useHelperApp:
-        if (preferredApp)
-          menu.selectedItem =
-            possibleAppMenuItems.filter(v => v.handlerApp.equals(preferredApp))[0];
-        break;
-      case kActionUsePlugin:
-        menu.selectedItem = pluginMenuItem;
-        break;
-      case Ci.nsIHandlerInfo.saveToDisk:
-        menu.selectedItem = saveMenuItem;
-        break;
-    }
-  },
-
-
-  // Sorting & Filtering
-
-  _sortColumn: null,
-
-  /**
-   * Sort the list when the user clicks on a column header.
-   */
-  sort(event) {
-    var column = event.target;
-
-    // If the user clicked on a new sort column, remove the direction indicator
-    // from the old column.
-    if (this._sortColumn && this._sortColumn != column)
-      this._sortColumn.removeAttribute("sortDirection");
-
-    this._sortColumn = column;
-
-    // Set (or switch) the sort direction indicator.
-    if (column.getAttribute("sortDirection") == "ascending")
-      column.setAttribute("sortDirection", "descending");
-    else
-      column.setAttribute("sortDirection", "ascending");
-
-    this._sortVisibleTypes();
-    this._rebuildView();
-  },
-
-  /**
-   * Sort the list of visible types by the current sort column/direction.
-   */
-  _sortVisibleTypes() {
-    if (!this._sortColumn)
-      return;
-
-    var t = this;
-
-    function sortByType(a, b) {
-      return t._describeType(a).toLowerCase().
-             localeCompare(t._describeType(b).toLowerCase());
-    }
-
-    function sortByAction(a, b) {
-      return t._describePreferredAction(a).toLowerCase().
-             localeCompare(t._describePreferredAction(b).toLowerCase());
-    }
-
-    switch (this._sortColumn.getAttribute("value")) {
-      case "type":
-        this._visibleTypes.sort(sortByType);
-        break;
-      case "action":
-        this._visibleTypes.sort(sortByAction);
-        break;
-    }
-
-    if (this._sortColumn.getAttribute("sortDirection") == "descending")
-      this._visibleTypes.reverse();
-  },
-
-  /**
-   * Filter the list when the user enters a filter term into the filter field.
-   */
-  filter() {
-    this._rebuildView();
-  },
-
-  focusFilterBox() {
-    this._filter.focus();
-    this._filter.select();
-  },
-
-
-  // Changes
-
-  onSelectAction(aActionItem) {
-    this._storingAction = true;
-
-    try {
-      this._storeAction(aActionItem);
-    } finally {
-      this._storingAction = false;
-    }
-  },
-
-  _storeAction(aActionItem) {
-    var typeItem = this._list.selectedItem;
-    var handlerInfo = this._handledTypes[typeItem.type];
-
-    let action = parseInt(aActionItem.getAttribute("action"));
-
-    // Set the plugin state if we're enabling or disabling a plugin.
-    if (action == kActionUsePlugin)
-      handlerInfo.enablePluginType();
-    else if (handlerInfo.pluginName && !handlerInfo.isDisabledPluginType)
-      handlerInfo.disablePluginType();
-
-    // Set the preferred application handler.
-    // We leave the existing preferred app in the list when we set
-    // the preferred action to something other than useHelperApp so that
-    // legacy datastores that don't have the preferred app in the list
-    // of possible apps still include the preferred app in the list of apps
-    // the user can choose to handle the type.
-    if (action == Ci.nsIHandlerInfo.useHelperApp)
-      handlerInfo.preferredApplicationHandler = aActionItem.handlerApp;
-
-    // Set the "always ask" flag.
-    if (action == Ci.nsIHandlerInfo.alwaysAsk)
-      handlerInfo.alwaysAskBeforeHandling = true;
-    else
-      handlerInfo.alwaysAskBeforeHandling = false;
-
-    // Set the preferred action.
-    handlerInfo.preferredAction = action;
-
-    handlerInfo.store();
-
-    // Make sure the handler info object is flagged to indicate that there is
-    // now some user configuration for the type.
-    handlerInfo.handledOnlyByPlugin = false;
-
-    // Update the action label and image to reflect the new preferred action.
-    typeItem.setAttribute("actionDescription",
-                          this._describePreferredAction(handlerInfo));
-    if (!this._setIconClassForPreferredAction(handlerInfo, typeItem)) {
-      typeItem.setAttribute("actionIcon",
-                            this._getIconURLForPreferredAction(handlerInfo));
-    }
-  },
-
-  manageApp(aEvent) {
-    // Don't let the normal "on select action" handler get this event,
-    // as we handle it specially ourselves.
-    aEvent.stopPropagation();
-
-    var typeItem = this._list.selectedItem;
-    var handlerInfo = this._handledTypes[typeItem.type];
-
-    let onComplete = () => {
-      // Rebuild the actions menu so that we revert to the previous selection,
-      // or "Always ask" if the previous default application has been removed
-      this.rebuildActionsMenu();
-
-      // update the richlistitem too. Will be visible when selecting another row
-      typeItem.setAttribute("actionDescription",
-                            this._describePreferredAction(handlerInfo));
-      if (!this._setIconClassForPreferredAction(handlerInfo, typeItem)) {
-        typeItem.setAttribute("actionIcon",
-                              this._getIconURLForPreferredAction(handlerInfo));
-      }
-    };
-
-    gSubDialog.open("chrome://browser/content/preferences/applicationManager.xul",
-                    "resizable=no", handlerInfo, onComplete);
-
-  },
-
-  chooseApp(aEvent) {
-    // Don't let the normal "on select action" handler get this event,
-    // as we handle it specially ourselves.
-    aEvent.stopPropagation();
-
-    var handlerApp;
-    let chooseAppCallback = aHandlerApp => {
-      // Rebuild the actions menu whether the user picked an app or canceled.
-      // If they picked an app, we want to add the app to the menu and select it.
-      // If they canceled, we want to go back to their previous selection.
-      this.rebuildActionsMenu();
-
-      // If the user picked a new app from the menu, select it.
-      if (aHandlerApp) {
-        let typeItem = this._list.selectedItem;
-        let actionsMenu =
-          document.getAnonymousElementByAttribute(typeItem, "class", "actionsMenu");
-        let menuItems = actionsMenu.menupopup.childNodes;
-        for (let i = 0; i < menuItems.length; i++) {
-          let menuItem = menuItems[i];
-          if (menuItem.handlerApp && menuItem.handlerApp.equals(aHandlerApp)) {
-            actionsMenu.selectedIndex = i;
-            this.onSelectAction(menuItem);
-            break;
-          }
-        }
-      }
-    };
-
-    if (AppConstants.platform == "win") {
-      var params = {};
-      var handlerInfo = this._handledTypes[this._list.selectedItem.type];
-
-      if (isFeedType(handlerInfo.type)) {
-        // MIME info will be null, create a temp object.
-        params.mimeInfo = this._mimeSvc.getFromTypeAndExtension(handlerInfo.type,
-                                                   handlerInfo.primaryExtension);
-      } else {
-        params.mimeInfo = handlerInfo.wrappedHandlerInfo;
-      }
-
-      params.title         = this._prefsBundle.getString("fpTitleChooseApp");
-      params.description   = handlerInfo.description;
-      params.filename      = null;
-      params.handlerApp    = null;
-
-      let onAppSelected = () => {
-        if (this.isValidHandlerApp(params.handlerApp)) {
-          handlerApp = params.handlerApp;
-
-          // Add the app to the type's list of possible handlers.
-          handlerInfo.addPossibleApplicationHandler(handlerApp);
-        }
-
-        chooseAppCallback(handlerApp);
-      };
-
-      gSubDialog.open("chrome://global/content/appPicker.xul",
-                      null, params, onAppSelected);
-    } else {
-      let winTitle = this._prefsBundle.getString("fpTitleChooseApp");
-      let fp = Cc["@mozilla.org/filepicker;1"].createInstance(Ci.nsIFilePicker);
-      let fpCallback = aResult => {
-        if (aResult == Ci.nsIFilePicker.returnOK && fp.file &&
-            this._isValidHandlerExecutable(fp.file)) {
-          handlerApp = Cc["@mozilla.org/uriloader/local-handler-app;1"].
-                       createInstance(Ci.nsILocalHandlerApp);
-          handlerApp.name = getFileDisplayName(fp.file);
-          handlerApp.executable = fp.file;
-
-          // Add the app to the type's list of possible handlers.
-          let handler = this._handledTypes[this._list.selectedItem.type];
-          handler.addPossibleApplicationHandler(handlerApp);
-
-          chooseAppCallback(handlerApp);
-        }
-      };
-
-      // Prompt the user to pick an app.  If they pick one, and it's a valid
-      // selection, then add it to the list of possible handlers.
-      fp.init(window, winTitle, Ci.nsIFilePicker.modeOpen);
-      fp.appendFilters(Ci.nsIFilePicker.filterApps);
-      fp.open(fpCallback);
-    }
-  },
-
-  // Mark which item in the list was last selected so we can reselect it
-  // when we rebuild the list or when the user returns to the prefpane.
-  onSelectionChanged() {
-    if (this._list.selectedItem)
-      this._list.setAttribute("lastSelectedType",
-                              this._list.selectedItem.getAttribute("type"));
-  },
-
-  _setIconClassForPreferredAction(aHandlerInfo, aElement) {
-    // If this returns true, the attribute that CSS sniffs for was set to something
-    // so you shouldn't manually set an icon URI.
-    // This removes the existing actionIcon attribute if any, even if returning false.
-    aElement.removeAttribute("actionIcon");
-
-    if (aHandlerInfo.alwaysAskBeforeHandling) {
-      aElement.setAttribute(APP_ICON_ATTR_NAME, "ask");
-      return true;
-    }
-
-    switch (aHandlerInfo.preferredAction) {
-      case Ci.nsIHandlerInfo.saveToDisk:
-        aElement.setAttribute(APP_ICON_ATTR_NAME, "save");
-        return true;
-
-      case Ci.nsIHandlerInfo.handleInternally:
-        if (isFeedType(aHandlerInfo.type)) {
-          aElement.setAttribute(APP_ICON_ATTR_NAME, "feed");
-          return true;
-        } else if (aHandlerInfo instanceof InternalHandlerInfoWrapper) {
-          aElement.setAttribute(APP_ICON_ATTR_NAME, "ask");
-          return true;
-        }
-        break;
-
-      case kActionUsePlugin:
-        aElement.setAttribute(APP_ICON_ATTR_NAME, "plugin");
-        return true;
-    }
-    aElement.removeAttribute(APP_ICON_ATTR_NAME);
-    return false;
-  },
-
-  _getIconURLForPreferredAction(aHandlerInfo) {
-    switch (aHandlerInfo.preferredAction) {
-      case Ci.nsIHandlerInfo.useSystemDefault:
-        return this._getIconURLForSystemDefault(aHandlerInfo);
-
-      case Ci.nsIHandlerInfo.useHelperApp:
-        let preferredApp = aHandlerInfo.preferredApplicationHandler;
-        if (this.isValidHandlerApp(preferredApp))
-          return this._getIconURLForHandlerApp(preferredApp);
-        // Explicit fall-through
-
-      // This should never happen, but if preferredAction is set to some weird
-      // value, then fall back to the generic application icon.
-      default:
-        return ICON_URL_APP;
-    }
-  },
-
-  _getIconURLForHandlerApp(aHandlerApp) {
-    if (aHandlerApp instanceof Ci.nsILocalHandlerApp)
-      return this._getIconURLForFile(aHandlerApp.executable);
-
-    if (aHandlerApp instanceof Ci.nsIWebHandlerApp)
-      return this._getIconURLForWebApp(aHandlerApp.uriTemplate);
-
-    if (aHandlerApp instanceof Ci.nsIWebContentHandlerInfo)
-      return this._getIconURLForWebApp(aHandlerApp.uri)
-
-    // We know nothing about other kinds of handler apps.
-    return "";
-  },
-
-  _getIconURLForFile(aFile) {
-    var fph = this._ioSvc.getProtocolHandler("file").
-              QueryInterface(Ci.nsIFileProtocolHandler);
-    var urlSpec = fph.getURLSpecFromFile(aFile);
-
-    return "moz-icon://" + urlSpec + "?size=16";
-  },
-
-  _getIconURLForWebApp(aWebAppURITemplate) {
-    var uri = this._ioSvc.newURI(aWebAppURITemplate);
-
-    // Unfortunately we can't use the favicon service to get the favicon,
-    // because the service looks in the annotations table for a record with
-    // the exact URL we give it, and users won't have such records for URLs
-    // they don't visit, and users won't visit the web app's URL template,
-    // they'll only visit URLs derived from that template (i.e. with %s
-    // in the template replaced by the URL of the content being handled).
-
-    if (/^https?$/.test(uri.scheme) && this._prefSvc.getBoolPref("browser.chrome.favicons"))
-      return uri.prePath + "/favicon.ico";
-
-    return "";
-  },
-
-  _getIconURLForSystemDefault(aHandlerInfo) {
-    // Handler info objects for MIME types on some OSes implement a property bag
-    // interface from which we can get an icon for the default app, so if we're
-    // dealing with a MIME type on one of those OSes, then try to get the icon.
-    if ("wrappedHandlerInfo" in aHandlerInfo) {
-      let wrappedHandlerInfo = aHandlerInfo.wrappedHandlerInfo;
-
-      if (wrappedHandlerInfo instanceof Ci.nsIMIMEInfo &&
-          wrappedHandlerInfo instanceof Ci.nsIPropertyBag) {
-        try {
-          let url = wrappedHandlerInfo.getProperty("defaultApplicationIconURL");
-          if (url)
-            return url + "?size=16";
-        } catch (ex) {}
-      }
-    }
-
-    // If this isn't a MIME type object on an OS that supports retrieving
-    // the icon, or if we couldn't retrieve the icon for some other reason,
-    // then use a generic icon.
-    return ICON_URL_APP;
-  },
-
-  // DOWNLOADS
-
-  /*
-   * Preferences:
-   *
-   * browser.download.useDownloadDir - bool
-   *   True - Save files directly to the folder configured via the
-   *   browser.download.folderList preference.
-   *   False - Always ask the user where to save a file and default to
-   *   browser.download.lastDir when displaying a folder picker dialog.
-   * browser.download.dir - local file handle
-   *   A local folder the user may have selected for downloaded files to be
-   *   saved. Migration of other browser settings may also set this path.
-   *   This folder is enabled when folderList equals 2.
-   * browser.download.lastDir - local file handle
-   *   May contain the last folder path accessed when the user browsed
-   *   via the file save-as dialog. (see contentAreaUtils.js)
-   * browser.download.folderList - int
-   *   Indicates the location users wish to save downloaded files too.
-   *   It is also used to display special file labels when the default
-   *   download location is either the Desktop or the Downloads folder.
-   *   Values:
-   *     0 - The desktop is the default download location.
-   *     1 - The system's downloads folder is the default download location.
-   *     2 - The default download location is elsewhere as specified in
-   *         browser.download.dir.
-   *     3 - The default download location is elsewhere as specified by
-   *         cloud storage API getDownloadFolder
-   * browser.download.downloadDir
-   *   deprecated.
-   * browser.download.defaultFolder
-   *   deprecated.
-   */
-
-  /**
-   * Enables/disables the folder field and Browse button based on whether a
-   * default download directory is being used.
-   */
-  readUseDownloadDir() {
-    var downloadFolder = document.getElementById("downloadFolder");
-    var chooseFolder = document.getElementById("chooseFolder");
-    var preference = document.getElementById("browser.download.useDownloadDir");
-    downloadFolder.disabled = !preference.value || preference.locked;
-    chooseFolder.disabled = !preference.value || preference.locked;
-
-    this.readCloudStorage().catch(Components.utils.reportError);
-    // don't override the preference's value in UI
-    return undefined;
-  },
-
-  /**
-   * Show/Hide the cloud storage radio button with provider name as label if
-   * cloud storage provider is in use.
-   * Select cloud storage radio button if browser.download.useDownloadDir is true
-   * and browser.download.folderList has value 3. Enables/disables the folder field
-   * and Browse button if cloud storage radio button is selected.
-   *
-   */
-  async readCloudStorage() {
-    // Get preferred provider in use display name
-    let providerDisplayName = await CloudStorage.getProviderIfInUse();
-    if (providerDisplayName) {
-      // Show cloud storage radio button with provider name in label
-      let saveToCloudRadio = document.getElementById("saveToCloud");
-      let cloudStrings = Services.strings.createBundle("resource://cloudstorage/preferences.properties");
-      saveToCloudRadio.label = cloudStrings.formatStringFromName("saveFilesToCloudStorage",
-                                                                 [providerDisplayName], 1);
-      saveToCloudRadio.hidden = false;
-
-      let useDownloadDirPref = document.getElementById("browser.download.useDownloadDir");
-      let folderListPref = document.getElementById("browser.download.folderList");
-
-      // Check if useDownloadDir is true and folderListPref is set to Cloud Storage value 3
-      // before selecting cloudStorageradio button. Disable folder field and Browse button if
-      // 'Save to Cloud Storage Provider' radio option is selected
-      if (useDownloadDirPref.value && folderListPref.value === 3) {
-        document.getElementById("saveWhere").selectedItem = saveToCloudRadio;
-        document.getElementById("downloadFolder").disabled = true;
-        document.getElementById("chooseFolder").disabled = true;
-      }
-    }
-  },
-
-  /**
-   * Handle clicks to 'Save To <custom path> or <system default downloads>' and
-   * 'Save to <cloud storage provider>' if cloud storage radio button is displayed in UI.
-   * Sets browser.download.folderList value and Enables/disables the folder field and Browse
-   * button based on option selected.
-   */
-  handleSaveToCommand(event) {
-    return this.handleSaveToCommandTask(event).catch(Components.utils.reportError);
-  },
-  async handleSaveToCommandTask(event) {
-    if (event.target.id !== "saveToCloud" && event.target.id !== "saveTo") {
-      return;
-    }
-    // Check if Save To Cloud Storage Provider radio option is displayed in UI
-    // before continuing.
-    let saveToCloudRadio = document.getElementById("saveToCloud");
-    if (!saveToCloudRadio.hidden) {
-      // When switching between SaveTo and SaveToCloud radio button
-      // with useDownloadDirPref value true, if selectedIndex is other than
-      // SaveTo radio button disable downloadFolder filefield and chooseFolder button
-      let saveWhere = document.getElementById("saveWhere");
-      let useDownloadDirPref = document.getElementById("browser.download.useDownloadDir");
-      if (useDownloadDirPref.value) {
-        let downloadFolder = document.getElementById("downloadFolder");
-        let chooseFolder = document.getElementById("chooseFolder");
-        downloadFolder.disabled = saveWhere.selectedIndex || useDownloadDirPref.locked;
-        chooseFolder.disabled = saveWhere.selectedIndex || useDownloadDirPref.locked;
-      }
-
-      // Set folderListPref value depending on radio option
-      // selected. folderListPref should be set to 3 if Save To Cloud Storage Provider
-      // option is selected. If user switch back to 'Save To' custom path or system
-      // default Downloads, check pref 'browser.download.dir' before setting respective
-      // folderListPref value. If currentDirPref is unspecified folderList should
-      // default to 1
-      let folderListPref = document.getElementById("browser.download.folderList");
-      let saveTo = document.getElementById("saveTo");
-      if (saveWhere.selectedItem == saveToCloudRadio) {
-        folderListPref.value = 3;
-      } else if (saveWhere.selectedItem == saveTo) {
-        let currentDirPref = document.getElementById("browser.download.dir");
-        folderListPref.value = currentDirPref.value ? await this._folderToIndex(currentDirPref.value) : 1;
-      }
-    }
-  },
-
-  /**
-   * Displays a file picker in which the user can choose the location where
-   * downloads are automatically saved, updating preferences and UI in
-   * response to the choice, if one is made.
-   */
-  chooseFolder() {
-    return this.chooseFolderTask().catch(Components.utils.reportError);
-  },
-  async chooseFolderTask() {
-    let bundlePreferences = document.getElementById("bundlePreferences");
-    let title = bundlePreferences.getString("chooseDownloadFolderTitle");
-    let folderListPref = document.getElementById("browser.download.folderList");
-    let currentDirPref = await this._indexToFolder(folderListPref.value);
-    let defDownloads = await this._indexToFolder(1);
-    let fp = Components.classes["@mozilla.org/filepicker;1"].
-             createInstance(Components.interfaces.nsIFilePicker);
-
-    fp.init(window, title, Components.interfaces.nsIFilePicker.modeGetFolder);
-    fp.appendFilters(Components.interfaces.nsIFilePicker.filterAll);
-    // First try to open what's currently configured
-    if (currentDirPref && currentDirPref.exists()) {
-      fp.displayDirectory = currentDirPref;
-    } else if (defDownloads && defDownloads.exists()) {
-      // Try the system's download dir
-      fp.displayDirectory = defDownloads;
-    } else {
-      // Fall back to Desktop
-      fp.displayDirectory = await this._indexToFolder(0);
-    }
-
-    let result = await new Promise(resolve => fp.open(resolve));
-    if (result != Components.interfaces.nsIFilePicker.returnOK) {
-      return;
-    }
-
-    let downloadDirPref = document.getElementById("browser.download.dir");
-    downloadDirPref.value = fp.file;
-    folderListPref.value = await this._folderToIndex(fp.file);
-    // Note, the real prefs will not be updated yet, so dnld manager's
-    // userDownloadsDirectory may not return the right folder after
-    // this code executes. displayDownloadDirPref will be called on
-    // the assignment above to update the UI.
-  },
-
-  /**
-   * Initializes the download folder display settings based on the user's
-   * preferences.
-   */
-  displayDownloadDirPref() {
-    this.displayDownloadDirPrefTask().catch(Components.utils.reportError);
-
-    // don't override the preference's value in UI
-    return undefined;
-  },
-
-  async displayDownloadDirPrefTask() {
-    var folderListPref = document.getElementById("browser.download.folderList");
-    var bundlePreferences = document.getElementById("bundlePreferences");
-    var downloadFolder = document.getElementById("downloadFolder");
-    var currentDirPref = document.getElementById("browser.download.dir");
-
-    // Used in defining the correct path to the folder icon.
-    var ios = Components.classes["@mozilla.org/network/io-service;1"]
-                        .getService(Components.interfaces.nsIIOService);
-    var fph = ios.getProtocolHandler("file")
-                 .QueryInterface(Components.interfaces.nsIFileProtocolHandler);
-    var iconUrlSpec;
-
-    let folderIndex = folderListPref.value;
-    if (folderIndex == 3) {
-      // When user has selected cloud storage, use value in currentDirPref to
-      // compute index to display download folder label and icon to avoid
-      // displaying blank downloadFolder label and icon on load of preferences UI
-      // Set folderIndex to 1 if currentDirPref is unspecified
-      folderIndex = currentDirPref.value ? await this._folderToIndex(currentDirPref.value) : 1;
-    }
-
-    // Display a 'pretty' label or the path in the UI.
-    if (folderIndex == 2) {
-      // Custom path selected and is configured
-      downloadFolder.label = this._getDisplayNameOfFile(currentDirPref.value);
-      iconUrlSpec = fph.getURLSpecFromFile(currentDirPref.value);
-    } else if (folderIndex == 1) {
-      // 'Downloads'
-      downloadFolder.label = bundlePreferences.getString("downloadsFolderName");
-      iconUrlSpec = fph.getURLSpecFromFile(await this._indexToFolder(1));
-    } else {
-      // 'Desktop'
-      downloadFolder.label = bundlePreferences.getString("desktopFolderName");
-      iconUrlSpec = fph.getURLSpecFromFile(await this._getDownloadsFolder("Desktop"));
-    }
-    downloadFolder.image = "moz-icon://" + iconUrlSpec + "?size=16";
-  },
-
-  /**
-   * Returns the textual path of a folder in readable form.
-   */
-  _getDisplayNameOfFile(aFolder) {
-    // TODO: would like to add support for 'Downloads on Macintosh HD'
-    //       for OS X users.
-    return aFolder ? aFolder.path : "";
-  },
-
-  /**
-   * Returns the Downloads folder.  If aFolder is "Desktop", then the Downloads
-   * folder returned is the desktop folder; otherwise, it is a folder whose name
-   * indicates that it is a download folder and whose path is as determined by
-   * the XPCOM directory service via the download manager's attribute
-   * defaultDownloadsDirectory.
-   *
-   * @throws if aFolder is not "Desktop" or "Downloads"
-   */
-  async _getDownloadsFolder(aFolder) {
-    switch (aFolder) {
-      case "Desktop":
-        var fileLoc = Components.classes["@mozilla.org/file/directory_service;1"]
-                                    .getService(Components.interfaces.nsIProperties);
-        return fileLoc.get("Desk", Components.interfaces.nsIFile);
-      case "Downloads":
-        let downloadsDir = await Downloads.getSystemDownloadsDirectory();
-        return new FileUtils.File(downloadsDir);
-    }
-    throw "ASSERTION FAILED: folder type should be 'Desktop' or 'Downloads'";
-  },
-
-  /**
-   * Determines the type of the given folder.
-   *
-   * @param   aFolder
-   *          the folder whose type is to be determined
-   * @returns integer
-   *          0 if aFolder is the Desktop or is unspecified,
-   *          1 if aFolder is the Downloads folder,
-   *          2 otherwise
-   */
-  async _folderToIndex(aFolder) {
-    if (!aFolder || aFolder.equals(await this._getDownloadsFolder("Desktop")))
-      return 0;
-    else if (aFolder.equals(await this._getDownloadsFolder("Downloads")))
-      return 1;
-    return 2;
-  },
-
-  /**
-   * Converts an integer into the corresponding folder.
-   *
-   * @param   aIndex
-   *          an integer
-   * @returns the Desktop folder if aIndex == 0,
-   *          the Downloads folder if aIndex == 1,
-   *          the folder stored in browser.download.dir
-   */
-  _indexToFolder(aIndex) {
-    switch (aIndex) {
-      case 0:
-        return this._getDownloadsFolder("Desktop");
-      case 1:
-        return this._getDownloadsFolder("Downloads");
-    }
-    var currentDirPref = document.getElementById("browser.download.dir");
-    return currentDirPref.value;
-  }
-};
-
-// Utilities
-
-function getFileDisplayName(file) {
-  if (AppConstants.platform == "win") {
-    if (file instanceof Ci.nsILocalFileWin) {
-      try {
-        return file.getVersionInfoField("FileDescription");
-      } catch (e) {}
-    }
-  }
-  if (AppConstants.platform == "macosx") {
-    if (file instanceof Ci.nsILocalFileMac) {
-      try {
-        return file.bundleDisplayName;
-      } catch (e) {}
-    }
-  }
-  return file.leafName;
-}
-
-function getLocalHandlerApp(aFile) {
-  var localHandlerApp = Cc["@mozilla.org/uriloader/local-handler-app;1"].
-                        createInstance(Ci.nsILocalHandlerApp);
-  localHandlerApp.name = getFileDisplayName(aFile);
-  localHandlerApp.executable = aFile;
-
-  return localHandlerApp;
-}
-
-/**
- * An enumeration of items in a JS array.
- *
- * FIXME: use ArrayConverter once it lands (bug 380839).
- *
- * @constructor
- */
-function ArrayEnumerator(aItems) {
-  this._index = 0;
-  this._contents = aItems;
-}
-
-ArrayEnumerator.prototype = {
-  _index: 0,
-
-  hasMoreElements() {
-    return this._index < this._contents.length;
-  },
-
-  getNext() {
-    return this._contents[this._index++];
-  }
-};
-
-function isFeedType(t) {
-  return t == TYPE_MAYBE_FEED || t == TYPE_MAYBE_VIDEO_FEED || t == TYPE_MAYBE_AUDIO_FEED;
-}
-
-// HandlerInfoWrapper
-
-/**
- * This object wraps nsIHandlerInfo with some additional functionality
- * the Applications prefpane needs to display and allow modification of
- * the list of handled types.
- *
- * We create an instance of this wrapper for each entry we might display
- * in the prefpane, and we compose the instances from various sources,
- * including plugins and the handler service.
- *
- * We don't implement all the original nsIHandlerInfo functionality,
- * just the stuff that the prefpane needs.
- *
- * In theory, all of the custom functionality in this wrapper should get
- * pushed down into nsIHandlerInfo eventually.
- */
-function HandlerInfoWrapper(aType, aHandlerInfo) {
-  this._type = aType;
-  this.wrappedHandlerInfo = aHandlerInfo;
-}
-
-HandlerInfoWrapper.prototype = {
-  // The wrapped nsIHandlerInfo object.  In general, this object is private,
-  // but there are a couple cases where callers access it directly for things
-  // we haven't (yet?) implemented, so we make it a public property.
-  wrappedHandlerInfo: null,
-
-
-  // Convenience Utils
-
-  _handlerSvc: Cc["@mozilla.org/uriloader/handler-service;1"].
-               getService(Ci.nsIHandlerService),
-
-  _prefSvc: Cc["@mozilla.org/preferences-service;1"].
-            getService(Ci.nsIPrefBranch),
-
-  _categoryMgr: Cc["@mozilla.org/categorymanager;1"].
-                getService(Ci.nsICategoryManager),
-
-  element(aID) {
-    return document.getElementById(aID);
-  },
-
-
-  // nsIHandlerInfo
-
-  // The MIME type or protocol scheme.
-  _type: null,
-  get type() {
-    return this._type;
-  },
-
-  get description() {
-    if (this.wrappedHandlerInfo.description)
-      return this.wrappedHandlerInfo.description;
-
-    if (this.primaryExtension) {
-      var extension = this.primaryExtension.toUpperCase();
-      return this.element("bundlePreferences").getFormattedString("fileEnding",
-                                                                  [extension]);
-    }
-
-    return this.type;
-  },
-
-  get preferredApplicationHandler() {
-    return this.wrappedHandlerInfo.preferredApplicationHandler;
-  },
-
-  set preferredApplicationHandler(aNewValue) {
-    this.wrappedHandlerInfo.preferredApplicationHandler = aNewValue;
-
-    // Make sure the preferred handler is in the set of possible handlers.
-    if (aNewValue)
-      this.addPossibleApplicationHandler(aNewValue)
-  },
-
-  get possibleApplicationHandlers() {
-    return this.wrappedHandlerInfo.possibleApplicationHandlers;
-  },
-
-  addPossibleApplicationHandler(aNewHandler) {
-    var possibleApps = this.possibleApplicationHandlers.enumerate();
-    while (possibleApps.hasMoreElements()) {
-      if (possibleApps.getNext().equals(aNewHandler))
-        return;
-    }
-    this.possibleApplicationHandlers.appendElement(aNewHandler);
-  },
-
-  removePossibleApplicationHandler(aHandler) {
-    var defaultApp = this.preferredApplicationHandler;
-    if (defaultApp && aHandler.equals(defaultApp)) {
-      // If the app we remove was the default app, we must make sure
-      // it won't be used anymore
-      this.alwaysAskBeforeHandling = true;
-      this.preferredApplicationHandler = null;
-    }
-
-    var handlers = this.possibleApplicationHandlers;
-    for (var i = 0; i < handlers.length; ++i) {
-      var handler = handlers.queryElementAt(i, Ci.nsIHandlerApp);
-      if (handler.equals(aHandler)) {
-        handlers.removeElementAt(i);
-        break;
-      }
-    }
-  },
-
-  get hasDefaultHandler() {
-    return this.wrappedHandlerInfo.hasDefaultHandler;
-  },
-
-  get defaultDescription() {
-    return this.wrappedHandlerInfo.defaultDescription;
-  },
-
-  // What to do with content of this type.
-  get preferredAction() {
-    // If we have an enabled plugin, then the action is to use that plugin.
-    if (this.pluginName && !this.isDisabledPluginType)
-      return kActionUsePlugin;
-
-    // If the action is to use a helper app, but we don't have a preferred
-    // handler app, then switch to using the system default, if any; otherwise
-    // fall back to saving to disk, which is the default action in nsMIMEInfo.
-    // Note: "save to disk" is an invalid value for protocol info objects,
-    // but the alwaysAskBeforeHandling getter will detect that situation
-    // and always return true in that case to override this invalid value.
-    if (this.wrappedHandlerInfo.preferredAction == Ci.nsIHandlerInfo.useHelperApp &&
-        !gMainPane.isValidHandlerApp(this.preferredApplicationHandler)) {
-      if (this.wrappedHandlerInfo.hasDefaultHandler)
-        return Ci.nsIHandlerInfo.useSystemDefault;
-      return Ci.nsIHandlerInfo.saveToDisk;
-    }
-
-    return this.wrappedHandlerInfo.preferredAction;
-  },
-
-  set preferredAction(aNewValue) {
-    // If the action is to use the plugin,
-    // we must set the preferred action to "save to disk".
-    // But only if it's not currently the preferred action.
-    if ((aNewValue == kActionUsePlugin) &&
-        (this.preferredAction != Ci.nsIHandlerInfo.saveToDisk)) {
-      aNewValue = Ci.nsIHandlerInfo.saveToDisk;
-    }
-
-    // We don't modify the preferred action if the new action is to use a plugin
-    // because handler info objects don't understand our custom "use plugin"
-    // value.  Also, leaving it untouched means that we can automatically revert
-    // to the old setting if the user ever removes the plugin.
-
-    if (aNewValue != kActionUsePlugin)
-      this.wrappedHandlerInfo.preferredAction = aNewValue;
-  },
-
-  get alwaysAskBeforeHandling() {
-    // If this type is handled only by a plugin, we can't trust the value
-    // in the handler info object, since it'll be a default based on the absence
-    // of any user configuration, and the default in that case is to always ask,
-    // even though we never ask for content handled by a plugin, so special case
-    // plugin-handled types by returning false here.
-    if (this.pluginName && this.handledOnlyByPlugin)
-      return false;
-
-    // If this is a protocol type and the preferred action is "save to disk",
-    // which is invalid for such types, then return true here to override that
-    // action.  This could happen when the preferred action is to use a helper
-    // app, but the preferredApplicationHandler is invalid, and there isn't
-    // a default handler, so the preferredAction getter returns save to disk
-    // instead.
-    if (!(this.wrappedHandlerInfo instanceof Ci.nsIMIMEInfo) &&
-        this.preferredAction == Ci.nsIHandlerInfo.saveToDisk)
-      return true;
-
-    return this.wrappedHandlerInfo.alwaysAskBeforeHandling;
-  },
-
-  set alwaysAskBeforeHandling(aNewValue) {
-    this.wrappedHandlerInfo.alwaysAskBeforeHandling = aNewValue;
-  },
-
-
-  // nsIMIMEInfo
-
-  // The primary file extension associated with this type, if any.
-  //
-  // XXX Plugin objects contain an array of MimeType objects with "suffixes"
-  // properties; if this object has an associated plugin, shouldn't we check
-  // those properties for an extension?
-  get primaryExtension() {
-    try {
-      if (this.wrappedHandlerInfo instanceof Ci.nsIMIMEInfo &&
-          this.wrappedHandlerInfo.primaryExtension)
-        return this.wrappedHandlerInfo.primaryExtension
-    } catch (ex) {}
-
-    return null;
-  },
-
-
-  // Plugin Handling
-
-  // A plugin that can handle this type, if any.
-  //
-  // Note: just because we have one doesn't mean it *will* handle the type.
-  // That depends on whether or not the type is in the list of types for which
-  // plugin handling is disabled.
-  plugin: null,
-
-  // Whether or not this type is only handled by a plugin or is also handled
-  // by some user-configured action as specified in the handler info object.
-  //
-  // Note: we can't just check if there's a handler info object for this type,
-  // because OS and user configuration is mixed up in the handler info object,
-  // so we always need to retrieve it for the OS info and can't tell whether
-  // it represents only OS-default information or user-configured information.
-  //
-  // FIXME: once handler info records are broken up into OS-provided records
-  // and user-configured records, stop using this boolean flag and simply
-  // check for the presence of a user-configured record to determine whether
-  // or not this type is only handled by a plugin.  Filed as bug 395142.
-  handledOnlyByPlugin: undefined,
-
-  get isDisabledPluginType() {
-    return this._getDisabledPluginTypes().indexOf(this.type) != -1;
-  },
-
-  _getDisabledPluginTypes() {
-    var types = "";
-
-    if (this._prefSvc.prefHasUserValue(PREF_DISABLED_PLUGIN_TYPES))
-      types = this._prefSvc.getCharPref(PREF_DISABLED_PLUGIN_TYPES);
-
-    // Only split if the string isn't empty so we don't end up with an array
-    // containing a single empty string.
-    if (types != "")
-      return types.split(",");
-
-    return [];
-  },
-
-  disablePluginType() {
-    var disabledPluginTypes = this._getDisabledPluginTypes();
-
-    if (disabledPluginTypes.indexOf(this.type) == -1)
-      disabledPluginTypes.push(this.type);
-
-    this._prefSvc.setCharPref(PREF_DISABLED_PLUGIN_TYPES,
-                              disabledPluginTypes.join(","));
-
-    // Update the category manager so existing browser windows update.
-    this._categoryMgr.deleteCategoryEntry("Gecko-Content-Viewers",
-                                          this.type,
-                                          false);
-  },
-
-  enablePluginType() {
-    var disabledPluginTypes = this._getDisabledPluginTypes();
-
-    var type = this.type;
-    disabledPluginTypes = disabledPluginTypes.filter(v => v != type);
-
-    this._prefSvc.setCharPref(PREF_DISABLED_PLUGIN_TYPES,
-                              disabledPluginTypes.join(","));
-
-    // Update the category manager so existing browser windows update.
-    this._categoryMgr.
-      addCategoryEntry("Gecko-Content-Viewers",
-                       this.type,
-                       "@mozilla.org/content/plugin/document-loader-factory;1",
-                       false,
-                       true);
-  },
-
-
-  // Storage
-
-  store() {
-    this._handlerSvc.store(this.wrappedHandlerInfo);
-  },
-
-
-  // Icons
-
-  get smallIcon() {
-    return this._getIcon(16);
-  },
-
-  _getIcon(aSize) {
-    if (this.primaryExtension)
-      return "moz-icon://goat." + this.primaryExtension + "?size=" + aSize;
-
-    if (this.wrappedHandlerInfo instanceof Ci.nsIMIMEInfo)
-      return "moz-icon://goat?size=" + aSize + "&contentType=" + this.type;
-
-    // FIXME: consider returning some generic icon when we can't get a URL for
-    // one (for example in the case of protocol schemes).  Filed as bug 395141.
-    return null;
-  }
-
-};
-
-
-// Feed Handler Info
-
-/**
- * This object implements nsIHandlerInfo for the feed types.  It's a separate
- * object because we currently store handling information for the feed type
- * in a set of preferences rather than the nsIHandlerService-managed datastore.
- *
- * This object inherits from HandlerInfoWrapper in order to get functionality
- * that isn't special to the feed type.
- *
- * XXX Should we inherit from HandlerInfoWrapper?  After all, we override
- * most of that wrapper's properties and methods, and we have to dance around
- * the fact that the wrapper expects to have a wrappedHandlerInfo, which we
- * don't provide.
- */
-
-function FeedHandlerInfo(aMIMEType) {
-  HandlerInfoWrapper.call(this, aMIMEType, null);
-}
-
-FeedHandlerInfo.prototype = {
-  __proto__: HandlerInfoWrapper.prototype,
-
-  // Convenience Utils
-
-  _converterSvc:
-    Cc["@mozilla.org/embeddor.implemented/web-content-handler-registrar;1"].
-    getService(Ci.nsIWebContentConverterService),
-
-  _shellSvc: AppConstants.HAVE_SHELL_SERVICE ? getShellService() : null,
-
-  // nsIHandlerInfo
-
-  get description() {
-    return this.element("bundlePreferences").getString(this._appPrefLabel);
-  },
-
-  get preferredApplicationHandler() {
-    switch (this.element(this._prefSelectedReader).value) {
-      case "client":
-        var file = this.element(this._prefSelectedApp).value;
-        if (file)
-          return getLocalHandlerApp(file);
-
-        return null;
-
-      case "web":
-        var uri = this.element(this._prefSelectedWeb).value;
-        if (!uri)
-          return null;
-        return this._converterSvc.getWebContentHandlerByURI(this.type, uri);
-
-      case "bookmarks":
-      default:
-        // When the pref is set to bookmarks, we handle feeds internally,
-        // we don't forward them to a local or web handler app, so there is
-        // no preferred handler.
-        return null;
-    }
-  },
-
-  set preferredApplicationHandler(aNewValue) {
-    if (aNewValue instanceof Ci.nsILocalHandlerApp) {
-      this.element(this._prefSelectedApp).value = aNewValue.executable;
-      this.element(this._prefSelectedReader).value = "client";
-    } else if (aNewValue instanceof Ci.nsIWebContentHandlerInfo) {
-      this.element(this._prefSelectedWeb).value = aNewValue.uri;
-      this.element(this._prefSelectedReader).value = "web";
-      // Make the web handler be the new "auto handler" for feeds.
-      // Note: we don't have to unregister the auto handler when the user picks
-      // a non-web handler (local app, Live Bookmarks, etc.) because the service
-      // only uses the "auto handler" when the selected reader is a web handler.
-      // We also don't have to unregister it when the user turns on "always ask"
-      // (i.e. preview in browser), since that also overrides the auto handler.
-      this._converterSvc.setAutoHandler(this.type, aNewValue);
-    }
-  },
-
-  _possibleApplicationHandlers: null,
-
-  get possibleApplicationHandlers() {
-    if (this._possibleApplicationHandlers)
-      return this._possibleApplicationHandlers;
-
-    // A minimal implementation of nsIMutableArray.  It only supports the two
-    // methods its callers invoke, namely appendElement and nsIArray::enumerate.
-    this._possibleApplicationHandlers = {
-      _inner: [],
-      _removed: [],
-
-      QueryInterface(aIID) {
-        if (aIID.equals(Ci.nsIMutableArray) ||
-            aIID.equals(Ci.nsIArray) ||
-            aIID.equals(Ci.nsISupports))
-          return this;
-
-        throw Cr.NS_ERROR_NO_INTERFACE;
-      },
-
-      get length() {
-        return this._inner.length;
-      },
-
-      enumerate() {
-        return new ArrayEnumerator(this._inner);
-      },
-
-      appendElement(aHandlerApp, aWeak) {
-        this._inner.push(aHandlerApp);
-      },
-
-      removeElementAt(aIndex) {
-        this._removed.push(this._inner[aIndex]);
-        this._inner.splice(aIndex, 1);
-      },
-
-      queryElementAt(aIndex, aInterface) {
-        return this._inner[aIndex].QueryInterface(aInterface);
-      }
-    };
-
-    // Add the selected local app if it's different from the OS default handler.
-    // Unlike for other types, we can store only one local app at a time for the
-    // feed type, since we store it in a preference that historically stores
-    // only a single path.  But we display all the local apps the user chooses
-    // while the prefpane is open, only dropping the list when the user closes
-    // the prefpane, for maximum usability and consistency with other types.
-    var preferredAppFile = this.element(this._prefSelectedApp).value;
-    if (preferredAppFile) {
-      let preferredApp = getLocalHandlerApp(preferredAppFile);
-      let defaultApp = this._defaultApplicationHandler;
-      if (!defaultApp || !defaultApp.equals(preferredApp))
-        this._possibleApplicationHandlers.appendElement(preferredApp);
-    }
-
-    // Add the registered web handlers.  There can be any number of these.
-    var webHandlers = this._converterSvc.getContentHandlers(this.type);
-    for (let webHandler of webHandlers)
-      this._possibleApplicationHandlers.appendElement(webHandler);
-
-    return this._possibleApplicationHandlers;
-  },
-
-  __defaultApplicationHandler: undefined,
-  get _defaultApplicationHandler() {
-    if (typeof this.__defaultApplicationHandler != "undefined")
-      return this.__defaultApplicationHandler;
-
-    var defaultFeedReader = null;
-    if (AppConstants.HAVE_SHELL_SERVICE) {
-      try {
-        defaultFeedReader = this._shellSvc.defaultFeedReader;
-      } catch (ex) {
-        // no default reader or _shellSvc is null
-      }
-    }
-
-    if (defaultFeedReader) {
-      let handlerApp = Cc["@mozilla.org/uriloader/local-handler-app;1"].
-                       createInstance(Ci.nsIHandlerApp);
-      handlerApp.name = getFileDisplayName(defaultFeedReader);
-      handlerApp.QueryInterface(Ci.nsILocalHandlerApp);
-      handlerApp.executable = defaultFeedReader;
-
-      this.__defaultApplicationHandler = handlerApp;
-    } else {
-      this.__defaultApplicationHandler = null;
-    }
-
-    return this.__defaultApplicationHandler;
-  },
-
-  get hasDefaultHandler() {
-    if (AppConstants.HAVE_SHELL_SERVICE) {
-      try {
-        if (this._shellSvc.defaultFeedReader)
-          return true;
-      } catch (ex) {
-        // no default reader or _shellSvc is null
-      }
-    }
-
-    return false;
-  },
-
-  get defaultDescription() {
-    if (this.hasDefaultHandler)
-      return this._defaultApplicationHandler.name;
-
-    // Should we instead return null?
-    return "";
-  },
-
-  // What to do with content of this type.
-  get preferredAction() {
-    switch (this.element(this._prefSelectedAction).value) {
-
-      case "bookmarks":
-        return Ci.nsIHandlerInfo.handleInternally;
-
-      case "reader": {
-        let preferredApp = this.preferredApplicationHandler;
-        let defaultApp = this._defaultApplicationHandler;
-
-        // If we have a valid preferred app, return useSystemDefault if it's
-        // the default app; otherwise return useHelperApp.
-        if (gMainPane.isValidHandlerApp(preferredApp)) {
-          if (defaultApp && defaultApp.equals(preferredApp))
-            return Ci.nsIHandlerInfo.useSystemDefault;
-
-          return Ci.nsIHandlerInfo.useHelperApp;
-        }
-
-        // The pref is set to "reader", but we don't have a valid preferred app.
-        // What do we do now?  Not sure this is the best option (perhaps we
-        // should direct the user to the default app, if any), but for now let's
-        // direct the user to live bookmarks.
-        return Ci.nsIHandlerInfo.handleInternally;
-      }
-
-      // If the action is "ask", then alwaysAskBeforeHandling will override
-      // the action, so it doesn't matter what we say it is, it just has to be
-      // something that doesn't cause the controller to hide the type.
-      case "ask":
-      default:
-        return Ci.nsIHandlerInfo.handleInternally;
-    }
-  },
-
-  set preferredAction(aNewValue) {
-    switch (aNewValue) {
-
-      case Ci.nsIHandlerInfo.handleInternally:
-        this.element(this._prefSelectedReader).value = "bookmarks";
-        break;
-
-      case Ci.nsIHandlerInfo.useHelperApp:
-        this.element(this._prefSelectedAction).value = "reader";
-        // The controller has already set preferredApplicationHandler
-        // to the new helper app.
-        break;
-
-      case Ci.nsIHandlerInfo.useSystemDefault:
-        this.element(this._prefSelectedAction).value = "reader";
-        this.preferredApplicationHandler = this._defaultApplicationHandler;
-        break;
-    }
-  },
-
-  get alwaysAskBeforeHandling() {
-    return this.element(this._prefSelectedAction).value == "ask";
-  },
-
-  set alwaysAskBeforeHandling(aNewValue) {
-    if (aNewValue == true)
-      this.element(this._prefSelectedAction).value = "ask";
-    else
-      this.element(this._prefSelectedAction).value = "reader";
-  },
-
-  // Whether or not we are currently storing the action selected by the user.
-  // We use this to suppress notification-triggered updates to the list when
-  // we make changes that may spawn such updates, specifically when we change
-  // the action for the feed type, which results in feed preference updates,
-  // which spawn "pref changed" notifications that would otherwise cause us
-  // to rebuild the view unnecessarily.
-  _storingAction: false,
-
-
-  // nsIMIMEInfo
-
-  get primaryExtension() {
-    return "xml";
-  },
-
-
-  // Storage
-
-  // Changes to the preferred action and handler take effect immediately
-  // (we write them out to the preferences right as they happen),
-  // so we when the controller calls store() after modifying the handlers,
-  // the only thing we need to store is the removal of possible handlers
-  // XXX Should we hold off on making the changes until this method gets called?
-  store() {
-    for (let app of this._possibleApplicationHandlers._removed) {
-      if (app instanceof Ci.nsILocalHandlerApp) {
-        let pref = this.element(PREF_FEED_SELECTED_APP);
-        var preferredAppFile = pref.value;
-        if (preferredAppFile) {
-          let preferredApp = getLocalHandlerApp(preferredAppFile);
-          if (app.equals(preferredApp))
-            pref.reset();
-        }
-      } else {
-        app.QueryInterface(Ci.nsIWebContentHandlerInfo);
-        this._converterSvc.removeContentHandler(app.contentType, app.uri);
-      }
-    }
-    this._possibleApplicationHandlers._removed = [];
-  },
-
-
-  // Icons
-
-  get smallIcon() {
-    return this._smallIcon;
-  }
-
-};
-
-var feedHandlerInfo = {
-  __proto__: new FeedHandlerInfo(TYPE_MAYBE_FEED),
-  _prefSelectedApp: PREF_FEED_SELECTED_APP,
-  _prefSelectedWeb: PREF_FEED_SELECTED_WEB,
-  _prefSelectedAction: PREF_FEED_SELECTED_ACTION,
-  _prefSelectedReader: PREF_FEED_SELECTED_READER,
-  _smallIcon: "chrome://browser/skin/feeds/feedIcon16.png",
-  _appPrefLabel: "webFeed"
-}
-
-var videoFeedHandlerInfo = {
-  __proto__: new FeedHandlerInfo(TYPE_MAYBE_VIDEO_FEED),
-  _prefSelectedApp: PREF_VIDEO_FEED_SELECTED_APP,
-  _prefSelectedWeb: PREF_VIDEO_FEED_SELECTED_WEB,
-  _prefSelectedAction: PREF_VIDEO_FEED_SELECTED_ACTION,
-  _prefSelectedReader: PREF_VIDEO_FEED_SELECTED_READER,
-  _smallIcon: "chrome://browser/skin/feeds/videoFeedIcon16.png",
-  _appPrefLabel: "videoPodcastFeed"
-}
-
-var audioFeedHandlerInfo = {
-  __proto__: new FeedHandlerInfo(TYPE_MAYBE_AUDIO_FEED),
-  _prefSelectedApp: PREF_AUDIO_FEED_SELECTED_APP,
-  _prefSelectedWeb: PREF_AUDIO_FEED_SELECTED_WEB,
-  _prefSelectedAction: PREF_AUDIO_FEED_SELECTED_ACTION,
-  _prefSelectedReader: PREF_AUDIO_FEED_SELECTED_READER,
-  _smallIcon: "chrome://browser/skin/feeds/audioFeedIcon16.png",
-  _appPrefLabel: "audioPodcastFeed"
-}
-
-/**
- * InternalHandlerInfoWrapper provides a basic mechanism to create an internal
- * mime type handler that can be enabled/disabled in the applications preference
- * menu.
- */
-function InternalHandlerInfoWrapper(aMIMEType) {
-  var mimeSvc = Cc["@mozilla.org/mime;1"].getService(Ci.nsIMIMEService);
-  var handlerInfo = mimeSvc.getFromTypeAndExtension(aMIMEType, null);
-
-  HandlerInfoWrapper.call(this, aMIMEType, handlerInfo);
-}
-
-InternalHandlerInfoWrapper.prototype = {
-  __proto__: HandlerInfoWrapper.prototype,
-
-  // Override store so we so we can notify any code listening for registration
-  // or unregistration of this handler.
-  store() {
-    HandlerInfoWrapper.prototype.store.call(this);
-    Services.obs.notifyObservers(null, this._handlerChanged);
-  },
-
-  get enabled() {
-    throw Cr.NS_ERROR_NOT_IMPLEMENTED;
-  },
-
-  get description() {
-    return this.element("bundlePreferences").getString(this._appPrefLabel);
-  }
-};
-
-var pdfHandlerInfo = {
-  __proto__: new InternalHandlerInfoWrapper(TYPE_PDF),
-  _handlerChanged: TOPIC_PDFJS_HANDLER_CHANGED,
-  _appPrefLabel: "portableDocumentFormat",
-  get enabled() {
-    return !Services.prefs.getBoolPref(PREF_PDFJS_DISABLED);
-  },
-};