Devtools: Fix hidden experiments keyboard shortcut

third_party/WebKit/Source/devtools/front_end/settings/SettingsScreen.js

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 69 matching lines @@
         this._tabbedPane.selectTab(name);
     },
 
     /**
      * @param {!Event} event
      */
     _keyDown: function(event)
     {
         var shiftKeyCode = 16;
         if (event.keyCode === shiftKeyCode && ++this._developerModeCounter > 5)
-            this.element.classList.add("settings-developer-mode");
+            this.contentElement.classList.add("settings-developer-mode");
     },
 
     __proto__: WebInspector.VBox.prototype
 }
 
 /**
  * @constructor
  * @extends {WebInspector.VBox}
  * @param {string} name
  * @param {string=} id
@@ skipping 966 matching lines @@
             var columnId = columns[i];
             var editElement = this._addInputElements.get(columnId);
             this._setEditElementValue(editElement, "");
         }
     },
 
     __proto__: WebInspector.SettingsList.prototype
 }
 
 WebInspector._settingsController = new WebInspector.SettingsController();