[DevTools] Teach MediaQueryInspector about disabling models while profiling.

Source/devtools/front_end/toolbox/MediaQueryInspector.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @constructor
  * @extends {WebInspector.View}
  * @implements {WebInspector.TargetManager.Observer}
  */
 WebInspector.MediaQueryInspector = function()
@@ skipping 49 matching lines @@
      * @param {!WebInspector.Target} target
      */
     targetRemoved: function(target)
     {
         if (target !== this._target)
             return;
         target.cssModel.removeEventListener(WebInspector.CSSStyleModel.Events.StyleSheetAdded, this._scheduleMediaQueriesUpdate, this);
         target.cssModel.removeEventListener(WebInspector.CSSStyleModel.Events.StyleSheetRemoved, this._scheduleMediaQueriesUpdate, this);
         target.cssModel.removeEventListener(WebInspector.CSSStyleModel.Events.StyleSheetChanged, this._scheduleMediaQueriesUpdate, this);
         target.cssModel.removeEventListener(WebInspector.CSSStyleModel.Events.MediaQueryResultChanged, this._scheduleMediaQueriesUpdate, this);
+        delete this._target;
     },
 
     /**
      * @param {number} offset
      * @param {number} scale
      */
     setAxisTransform: function(offset, scale)
     {
         if (this._offset === offset && Math.abs(this._scale - scale) < 1e-8)
             return;
@@ skipping 43 matching lines @@
             setWidth(model.minWidthExpression().computedLength());
         else
             setWidth(model.maxWidthExpression().computedLength());
     },
 
     /**
      * @param {!Event} event
      */
     _onContextMenu: function(event)
     {
+        if (!this._target || !this._target.cssModel.isEnabled())
+            return;
+
         var mediaQueryMarker = event.target.enclosingNodeOrSelfWithClass("media-inspector-marker");
         if (!mediaQueryMarker)
             return;
 
         var locations = mediaQueryMarker._locations;
         var uiLocations = new Map();
         for (var i = 0; i < locations.length; ++i) {
             var uiLocation = WebInspector.cssWorkspaceBinding.rawLocationToUILocation(locations[i]);
             if (!uiLocation)
                 continue;
@@ skipping 24 matching lines @@
         if (!this._enabled)
             return;
         this._mediaThrottler.schedule(this._refetchMediaQueries.bind(this));
     },
 
     /**
      * @param {!WebInspector.Throttler.FinishCallback} finishCallback
      */
     _refetchMediaQueries: function(finishCallback)
     {
-        if (!this._enabled) {
+        if (!this._enabled || !this._target) {
             finishCallback();
             return;
         }
 
         /**
          * @param {!Array.<!WebInspector.CSSMedia>} cssMedias
          * @this {!WebInspector.MediaQueryInspector}
          */
         function callback(cssMedias)
         {
@@ skipping 313 matching lines @@
     },
 
     /**
      * @return {boolean}
      */
     active: function()
     {
         return this._active;
     }
 }