--- a/browser/base/content/browser-gestureSupport.js
+++ b/browser/base/content/browser-gestureSupport.js
@@ -982,35 +982,32 @@ var gHistorySwipeAnimation = {
    */
   _takeSnapshot: function HSA__takeSnapshot() {
     if (!this._readyToTakeSnapshots()) {
       return;
     }
 
     let canvas = null;
 
-    try {
-      let browser = gBrowser.selectedBrowser;
-      let r = browser.getBoundingClientRect();
-      canvas = document.createElementNS("http://www.w3.org/1999/xhtml",
-                                        "canvas");
-      canvas.mozOpaque = true;
-      let scale = window.devicePixelRatio;
-      canvas.width = r.width * scale;
-      canvas.height = r.height * scale;
-      let ctx = canvas.getContext("2d");
-      let zoom = browser.markupDocumentViewer.fullZoom * scale;
-      ctx.scale(zoom, zoom);
-      ctx.drawWindow(browser.contentWindow,
-                     0, 0, canvas.width / zoom, canvas.height / zoom, "white",
-                     ctx.DRAWWINDOW_DO_NOT_FLUSH | ctx.DRAWWINDOW_DRAW_VIEW |
-                     ctx.DRAWWINDOW_ASYNC_DECODE_IMAGES |
-                     ctx.DRAWWINDOW_USE_WIDGET_LAYERS);
-    } finally {
-    }
+    let browser = gBrowser.selectedBrowser;
+    let r = browser.getBoundingClientRect();
+    canvas = document.createElementNS("http://www.w3.org/1999/xhtml",
+                                      "canvas");
+    canvas.mozOpaque = true;
+    let scale = window.devicePixelRatio;
+    canvas.width = r.width * scale;
+    canvas.height = r.height * scale;
+    let ctx = canvas.getContext("2d");
+    let zoom = browser.markupDocumentViewer.fullZoom * scale;
+    ctx.scale(zoom, zoom);
+    ctx.drawWindow(browser.contentWindow,
+                   0, 0, canvas.width / zoom, canvas.height / zoom, "white",
+                   ctx.DRAWWINDOW_DO_NOT_FLUSH | ctx.DRAWWINDOW_DRAW_VIEW |
+                   ctx.DRAWWINDOW_ASYNC_DECODE_IMAGES |
+                   ctx.DRAWWINDOW_USE_WIDGET_LAYERS);
 
     TelemetryStopwatch.start("FX_GESTURE_INSTALL_SNAPSHOT_OF_PAGE");
     try {
       this._installCurrentPageSnapshot(canvas);
       this._assignSnapshotToCurrentBrowser(canvas);
     } finally {
       TelemetryStopwatch.finish("FX_GESTURE_INSTALL_SNAPSHOT_OF_PAGE");
     }

--- a/browser/components/nsBrowserContentHandler.js
+++ b/browser/components/nsBrowserContentHandler.js
@@ -733,17 +733,17 @@ nsDefaultCommandLineHandler.prototype = 
       // urls launched after the initial launch will be lost.
       if (!this._haveProfile) {
         try {
           // This will throw when a profile has not been selected.
           var dir = Services.dirsvc.get("ProfD", Components.interfaces.nsILocalFile);
           this._haveProfile = true;
         }
         catch (e) {
-          while ((ar = cmdLine.handleFlagWithParam("url", false))) { }
+          while ((ar = cmdLine.handleFlagWithParam("url", false)));
           cmdLine.preventDefault = true;
         }
       }
     }
 
     let redirectWinSearch = false;
     if (AppConstants.isPlatformAndVersionAtLeast("win", "10")) {
       redirectWinSearch = Services.prefs.getBoolPref("browser.search.redirectWindowsSearch");

--- a/toolkit/.eslintrc
+++ b/toolkit/.eslintrc
@@ -66,17 +66,17 @@
 
     // No labels
     "no-labels": 2,
 
     // If an if block ends with a return no need for an else block
     // "no-else-return": 2,
 
     // No empty statements
-    // "no-empty": 2,
+    "no-empty": [2, "allowEmptyCatch": true],
 
     // No empty character classes in regex
     "no-empty-character-class": 2,
 
     // Disallow empty destructuring
     "no-empty-pattern": 2,
 
     // No assiging to exception variable

--- a/toolkit/components/narrate/Narrator.jsm
+++ b/toolkit/components/narrate/Narrator.jsm
@@ -211,17 +211,21 @@ Narrator.prototype = {
       voice: this._getVoice(speechOptions.voice)
     };
 
     this._stopped = false;
     return this._detectLanguage().then(() => {
       let tw = this._treeWalker;
       if (!this._isParagraphInView(tw.currentNode)) {
         tw.currentNode = tw.root;
-        while (tw.nextNode() && !this._isParagraphInView(tw.currentNode)) {}
+        while (tw.nextNode()) {
+          if (this._isParagraphInView(tw.currentNode)) {
+            break;
+          }
+        }
         // _speakInner will advance to the next node for us, so we need
         // to have it one paragraph back from the first visible one.
         tw.previousNode();
       }
 
       return this._speakInner();
     });
   },

--- a/toolkit/components/telemetry/tests/unit/test_ThreadHangStats.js
+++ b/toolkit/components/telemetry/tests/unit/test_ThreadHangStats.js
@@ -34,25 +34,23 @@ function run_test() {
   // Run three events in the event loop:
   // the first event causes a transient hang;
   // the second event causes a permanent hang;
   // the third event checks results from previous events.
 
   do_execute_soon(() => {
     // Cause a hang lasting 1 second (transient hang).
     let startTime = Date.now();
-    while ((Date.now() - startTime) < 1000) {
-    }
+    while ((Date.now() - startTime) < 1000);
   });
 
   do_execute_soon(() => {
     // Cause a hang lasting 10 seconds (permanent hang).
     let startTime = Date.now();
-    while ((Date.now() - startTime) < 10000) {
-    }
+    while ((Date.now() - startTime) < 10000);
   });
 
   do_execute_soon(() => {
     do_test_pending();
 
     let check_results = () => {
       let endHangs = getMainThreadHangStats();
 

--- a/toolkit/modules/GMPUtils.jsm
+++ b/toolkit/modules/GMPUtils.jsm
@@ -63,18 +63,16 @@ this.GMPUtils = {
    * @param   aPlugin
    *          The plugin to check.
    */
   _isPluginSupported: function(aPlugin) {
     if (this._isPluginForceSupported(aPlugin)) {
       return true;
     }
     if (aPlugin.id == EME_ADOBE_ID) {
-      if (Services.appinfo.OS != "WINNT") {
-      }
       // Windows Vista and later only supported by Adobe EME.
       return AppConstants.isPlatformAndVersionAtLeast("win", "6");
     } else if (aPlugin.id == WIDEVINE_ID) {
       // The Widevine plugin is available for Windows versions Vista and later,
       // Mac OSX, and Linux.
       return AppConstants.isPlatformAndVersionAtLeast("win", "6") ||
              AppConstants.platform == "macosx" ||
              AppConstants.platform == "linux";