DevTools: make paint profiler target-aware

Source/devtools/front_end/sdk/Target.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 {Protocol.Agents}
  * @param {string} name
  * @param {!InspectorBackendClass.Connection} connection
  * @param {function(!WebInspector.Target)=} callback
  */
 WebInspector.Target = function(name, connection, callback)
 {
     Protocol.Agents.call(this, connection.agentsMap());
+    /** @type {!WeakReference.<!WebInspector.Target>} */
+    this._weakReference = new WeakReference(this);
     this._name = name;
     this._connection = connection;
     /** @type {boolean} */
     this.isMainFrontend = false;
     this._id = WebInspector.Target._nextId++;
     /** @type {boolean} */
     this.canScreencast = false;
     this.pageAgent().canScreencast(this._initializeCapability.bind(this, "canScreencast", null));
 
     /** @type {boolean} */
@@ skipping 24 matching lines @@
     /**
      *
      * @return {string}
      */
     name: function()
     {
         return this._name;
     },
 
     /**
+     * @return {!WeakReference.<!WebInspector.Target>}
+     */
+    weakReference: function()
+    {
+       return this._weakReference;
+    },
+
+    /**
      * @param {string} name
      * @param {function()|null} callback
      * @param {?Protocol.Error} error
      * @param {*} result
      */
     _initializeCapability: function(name, callback, error, result)
     {
         this[name] = result;
         if (!Capabilities[name])
             Capabilities[name] = result;
@@ skipping 104 matching lines @@
      * @return {boolean}
      */
     isMobile: function()
     {
         // FIXME: either add a separate capability or rename canScreencast to isMobile.
         return this.canScreencast;
     },
 
     dispose: function()
     {
+        this._weakReference.clear();
         this.debuggerModel.dispose();
         this.networkManager.dispose();
         this.cpuProfilerModel.dispose();
     },
 
     __proto__: Protocol.Agents.prototype
 }
 
 /**
  * @constructor
@@ skipping 163 matching lines @@
     target: function()
     {
         return this._target;
     }
 }
 
 /**
  * @type {!WebInspector.TargetManager}
  */
 WebInspector.targetManager = new WebInspector.TargetManager();