Bug 1353013 - Be less aggressive about preloading about:newtab. r?florian draft
authorMike Conley <mconley@mozilla.com>
Thu, 24 Aug 2017 15:23:18 -0700
changeset 667848 88a74b30e5a11b6aad57596cd59352b938523ce4
parent 667847 9d2183319abea2acb78814afc8a1bf92553dd8e1
child 667849 8215658cda7beac6074da328f624fb1253629c41
child 668403 f1a908dead8619a665d135baf4d91750ff25035b
push id80876
push usermconley@mozilla.com
push dateWed, 20 Sep 2017 21:34:56 +0000
reviewersflorian
bugs1353013
milestone57.0a1
Bug 1353013 - Be less aggressive about preloading about:newtab. r?florian Based on a patch that Dão Gottwald <dao+bmo@mozilla.com> wrote. We used to preload about:newtab as soon as a tab had finished being opened, which meant that the first opened tab was _never_ preloaded, and that we risked janking the browser immediately after the user opened a new tab (which is, arguably, the worst time to do it, since the user is probably about to navigate that tab somewhere). This patch makes it so that about:newtab is preloaded after: 1) 1 second of user inactivity, and 2) When we have at least 40ms of idle time to spend in an idle callback. The 1s and 40ms thresholds were chosen arbitrarily, and we might tune them over time. MozReview-Commit-ID: J5xkPQvCdW6
browser/base/content/browser.js
browser/base/content/tabbrowser.xml
toolkit/modules/Services.jsm
toolkit/modules/tests/xpcshell/test_Services.js
--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -1759,16 +1759,21 @@ var gBrowserInit = {
       try {
         DownloadsCommon.initializeAllDataLinks();
         Cu.import("resource:///modules/DownloadsTaskbar.jsm", {})
           .DownloadsTaskbar.registerIndicator(window);
       } catch (ex) {
         Cu.reportError(ex);
       }
     }, {timeout: 10000});
+
+    scheduleIdleTask(() => {
+      // Prepare preloaded browser for the next new tab to open.
+      gBrowser.requestPreloadBrowser();
+    });
   },
 
   // Returns the URI(s) to load at startup.
   get _uriToLoadPromise() {
     delete this._uriToLoadPromise;
     return this._uriToLoadPromise = new Promise(resolve => {
       // window.arguments[0]: URI to load (string), or an nsIArray of
       //                      nsISupportsStrings to load, or a xul:tab of
--- a/browser/base/content/tabbrowser.xml
+++ b/browser/base/content/tabbrowser.xml
@@ -2109,25 +2109,65 @@
             // and the URL is "about:newtab". We do not support preloading for
             // custom newtab URLs.
             return Services.prefs.getBoolPref("browser.newtab.preload") &&
                    !aboutNewTabService.overridden;
           ]]>
         </body>
       </method>
 
+      <field name="_preloadBrowserMinUserIdleSeconds">1</field>
+      <field name="_preloadBrowserMinIdlePeriodMs">40</field>
+      <method name="requestPreloadBrowser">
+        <body><![CDATA[
+          // Do nothing if we have a preloaded browser already or we're about
+          // to create one or preloading is disabled.
+          if (this._preloadedBrowser ||
+              this._preloadBrowserIdleObserver ||
+              !this._isPreloadingEnabled()) {
+            return;
+          }
+
+          this._preloadBrowserIdleObserver = (aSubject, aTopic) => {
+            if (aTopic != "idle") {
+              return;
+            }
+
+            Services.idle.removeIdleObserver(this._preloadBrowserIdleObserver,
+                                             this._preloadBrowserMinUserIdleSeconds);
+            this._preloadBrowserIdleObserver = null;
+
+            let idleCallback = deadline => {
+              if (deadline.timeRemaining() < this._preloadBrowserMinIdlePeriodMs) {
+                window.requestIdleCallback(idleCallback);
+              } else {
+                this._createPreloadBrowser();
+              }
+            };
+            window.requestIdleCallback(idleCallback);
+          };
+          Services.idle.addIdleObserver(this._preloadBrowserIdleObserver, this._preloadBrowserMinUserIdleSeconds);
+        ]]></body>
+      </method>
+
       <method name="_createPreloadBrowser">
         <body>
           <![CDATA[
             // Do nothing if we have a preloaded browser already
             // or preloading of newtab pages is disabled.
             if (this._preloadedBrowser || !this._isPreloadingEnabled()) {
               return;
             }
 
+            if (this._preloadBrowserIdleObserver) {
+              Services.idle.removeIdleObserver(this._preloadBrowserIdleObserver,
+                                               this._preloadBrowserMinUserIdleSeconds);
+              this._preloadBrowserIdleObserver = null;
+            }
+
             let remoteType =
               E10SUtils.getRemoteTypeForURI(BROWSER_NEW_TAB_URL,
                                             gMultiProcessBrowser);
             let browser = this._createBrowser({isPreloadBrowser: true, remoteType});
             this._preloadedBrowser = browser;
 
             let notificationbox = this.getNotificationBox(browser);
             this.mPanelContainer.appendChild(notificationbox);
@@ -5944,16 +5984,22 @@
             window.messageManager.removeMessageListener("contextmenu", this);
 
             if (this._switcher) {
               this._switcher.destroy();
             }
           }
 
           Services.prefs.removeObserver("accessibility.typeaheadfind", this);
+
+          if (this._preloadBrowserIdleObserver) {
+            Services.idle.removeIdleObserver(this._preloadBrowserIdleObserver,
+                                             this._preloadBrowserMinUserIdleSeconds);
+            this._preloadBrowserIdleObserver = null;
+          }
         ]]>
       </destructor>
 
       <field name="_soundPlayingAttrRemovalTimer">0</field>
       <field name="_hoverTabTimer">null</field>
     </implementation>
 
     <handlers>
@@ -7017,17 +7063,17 @@
           // XXXmano: this is a temporary workaround for bug 345399
           // We need to manually update the scroll buttons disabled state
           // if a tab was inserted to the overflow area or removed from it
           // without any scrolling and when the tabbar has already
           // overflowed.
           this.mTabstrip._updateScrollButtonsDisabledState();
 
           // Preload the next about:newtab if there isn't one already.
-          this.tabbrowser._createPreloadBrowser();
+          this.tabbrowser.requestPreloadBrowser();
         ]]></body>
       </method>
 
       <method name="_canAdvanceToTab">
         <parameter name="aTab"/>
         <body>
         <![CDATA[
           return !aTab.closing;
--- a/toolkit/modules/Services.jsm
+++ b/toolkit/modules/Services.jsm
@@ -72,16 +72,17 @@ var initTable = {
   cache2: ["@mozilla.org/netwerk/cache-storage-service;1", "nsICacheStorageService"],
   cpmm: ["@mozilla.org/childprocessmessagemanager;1", "nsIMessageSender"],
   console: ["@mozilla.org/consoleservice;1", "nsIConsoleService"],
   cookies: ["@mozilla.org/cookiemanager;1", "nsICookieManager2"],
   downloads: ["@mozilla.org/download-manager;1", "nsIDownloadManager"],
   droppedLinkHandler: ["@mozilla.org/content/dropped-link-handler;1", "nsIDroppedLinkHandler"],
   els: ["@mozilla.org/eventlistenerservice;1", "nsIEventListenerService"],
   eTLD: ["@mozilla.org/network/effective-tld-service;1", "nsIEffectiveTLDService"],
+  idle: ["@mozilla.org/widget/idleservice;1", "nsIIdleService"],
   intl: ["@mozilla.org/mozintl;1", "mozIMozIntl"],
   locale: ["@mozilla.org/intl/localeservice;1", "mozILocaleService"],
   logins: ["@mozilla.org/login-manager;1", "nsILoginManager"],
   obs: ["@mozilla.org/observer-service;1", "nsIObserverService"],
   perms: ["@mozilla.org/permissionmanager;1", "nsIPermissionManager"],
   prompt: ["@mozilla.org/embedcomp/prompt-service;1", "nsIPromptService"],
   scriptloader: ["@mozilla.org/moz/jssubscript-loader;1", "mozIJSSubScriptLoader"],
   scriptSecurityManager: ["@mozilla.org/scriptsecuritymanager;1", "nsIScriptSecurityManager"],
--- a/toolkit/modules/tests/xpcshell/test_Services.js
+++ b/toolkit/modules/tests/xpcshell/test_Services.js
@@ -37,16 +37,17 @@ function run_test() {
   checkService("dirsvc", Ci.nsIDirectoryService);
   checkService("dirsvc", Ci.nsIProperties);
   checkService("DOMRequest", Ci.nsIDOMRequestService);
   checkService("domStorageManager", Ci.nsIDOMStorageManager);
   checkService("downloads", Ci.nsIDownloadManager);
   checkService("droppedLinkHandler", Ci.nsIDroppedLinkHandler);
   checkService("eTLD", Ci.nsIEffectiveTLDService);
   checkService("focus", Ci.nsIFocusManager);
+  checkService("idle", Ci.nsIIdleService);
   checkService("io", Ci.nsIIOService);
   checkService("io", Ci.nsIIOService2);
   checkService("intl", Ci.mozIMozIntl);
   checkService("locale", Ci.mozILocaleService);
   checkService("logins", Ci.nsILoginManager);
   checkService("obs", Ci.nsIObserverService);
   checkService("perms", Ci.nsIPermissionManager);
   checkService("prefs", Ci.nsIPrefBranch);