[DevTools] Move user agent override to responsive design toolbar.

Source/devtools/front_end/common/Settings.js

 /*
  * Copyright (C) 2009 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 72 matching lines @@
     this.messageLevelFilters = this.createSetting("messageLevelFilters", {});
     this.splitVerticallyWhenDockedToRight = this.createSetting("splitVerticallyWhenDockedToRight", true);
     this.visiblePanels = this.createSetting("visiblePanels", {});
     this.shortcutPanelSwitch = this.createSetting("shortcutPanelSwitch", false);
     this.showWhitespacesInEditor = this.createSetting("showWhitespacesInEditor", false);
     this.skipStackFramesSwitch = this.createSetting("skipStackFramesSwitch", false);
     this.skipStackFramesPattern = this.createRegExpSetting("skipStackFramesPattern", "");
     this.pauseOnExceptionEnabled = this.createSetting("pauseOnExceptionEnabled", false);
     this.pauseOnCaughtException = this.createSetting("pauseOnCaughtException", false);
     this.enableAsyncStackTraces = this.createSetting("enableAsyncStackTraces", false);
-    this.responsiveDesignMode = this.createSetting("responsiveDesignMode", false);
+
+    this.responsiveDesign = {};
+    this.responsiveDesign.enabled = this.createSetting("responsiveDesign.enabled", false);
 }
 
 WebInspector.Settings.prototype = {
     /**
      * @param {string} key
      * @param {*} defaultValue
      * @return {!WebInspector.Setting}
      */
     createSetting: function(key, defaultValue)
     {
@@ skipping 650 matching lines @@
 
     _fireChangedIfNeeded: function()
     {
         var newValue = this._calculateValue();
         if (newValue === this._value)
             return;
         this._value = newValue;
         this._eventSupport.dispatchEventToListeners(this._name, this._value);
     }
 }