DevTools: Process correctly a disconnection during target initialization

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
+ * @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;
     connection.addEventListener(InspectorBackendClass.Connection.Events.Disconnected, this._onDisconnect, this);
     this._id = WebInspector.Target._nextId++;
@@ skipping 66 matching lines @@
     /**
      * @param {string} capability
      * @return {boolean}
      */
     hasCapability: function(capability)
     {
         return !!this._capabilities[capability];
     },
 
     /**
-     * @param {function(!WebInspector.Target)=} callback
+     * @param {function(?WebInspector.Target)=} callback
      */
     _loadedWithCapabilities: function(callback)
     {
+        if (this._connection.isClosed()) {
+            callback(null);
+            return;
+        }
+
         /** @type {!WebInspector.ConsoleModel} */
         this.consoleModel = new WebInspector.ConsoleModel(this);
 
         /** @type {!WebInspector.NetworkManager} */
         this.networkManager = new WebInspector.NetworkManager(this);
 
         /** @type {!WebInspector.ResourceTreeModel} */
         this.resourceTreeModel = new WebInspector.ResourceTreeModel(this);
         if (!WebInspector.resourceTreeModel)
             WebInspector.resourceTreeModel = this.resourceTreeModel;
@@ skipping 214 matching lines @@
      * @param {!WebInspector.TargetManager.Observer} targetObserver
      */
     unobserveTargets: function(targetObserver)
     {
         this._observers.remove(targetObserver);
     },
 
     /**
      * @param {string} name
      * @param {!InspectorBackendClass.Connection} connection
-     * @param {function(!WebInspector.Target)=} callback
+     * @param {function(?WebInspector.Target)=} callback
      */
     createTarget: function(name, connection, callback)
     {
         var target = new WebInspector.Target(name, connection, callbackWrapper.bind(this));
 
         /**
          * @this {WebInspector.TargetManager}
-         * @param {!WebInspector.Target} newTarget
+         * @param {?WebInspector.Target} newTarget
          */
         function callbackWrapper(newTarget)
         {
-            this.addTarget(newTarget);
+            if (newTarget)
+                this.addTarget(newTarget);
             if (callback)
                 callback(newTarget);
         }
     },
 
     /**
      * @param {!WebInspector.Target} target
      */
     addTarget: function(target)
     {
@@ skipping 63 matching lines @@
     /**
      * @param {!WebInspector.Target} target
      */
     targetRemoved: function(target) { },
 }
 
 /**
  * @type {!WebInspector.TargetManager}
  */
 WebInspector.targetManager = new WebInspector.TargetManager();