DevTools: Avoid exception when inspecting blob-based workers

Source/devtools/front_end/sdk/WorkerTargetManager.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
  * @param {!WebInspector.Target} mainTarget
  * @param {!WebInspector.TargetManager} targetManager
  */
 WebInspector.WorkerTargetManager = function(mainTarget, targetManager)
 {
     this._mainTarget = mainTarget;
     this._targetManager = targetManager;
     mainTarget.workerManager.addEventListener(WebInspector.WorkerManager.Events.WorkerAdded, this._onWorkerAdded, this);
+    mainTarget.workerManager.addEventListener(WebInspector.WorkerManager.Events.WorkersCleared, this._onWorkersCleared, this);
     WebInspector.profilingLock().addEventListener(WebInspector.Lock.Events.StateChanged, this._onProfilingStateChanged, this);
     this._onProfilingStateChanged();
+    this._lastAnonymousTargetId = 0;
 }
 
 WebInspector.WorkerTargetManager.prototype = {
     _onProfilingStateChanged: function()
     {
         var acquired = WebInspector.profilingLock().isAcquired();
         this._mainTarget.workerAgent().setAutoconnectToWorkers(!acquired);
     },
 
     /**
      * @param {!WebInspector.Event} event
      */
     _onWorkerAdded: function(event)
     {
         var data = /** @type {{workerId: number, url: string, inspectorConnected: boolean}} */ (event.data);
         new WebInspector.WorkerConnection(this._mainTarget, data.workerId, data.inspectorConnected, onConnectionReady.bind(this));
 
         /**
          * @this {WebInspector.WorkerTargetManager}
          * @param {!InspectorBackendClass.Connection} connection
          */
         function onConnectionReady(connection)
         {
-            this._targetManager.createTarget(WebInspector.UIString("Worker %s", data.url.asParsedURL().lastPathComponent), connection, targetCreated)
+            var parsedURL = data.url.asParsedURL();
+            var workerId = parsedURL ? parsedURL.lastPathComponent : "#" + (++this._lastAnonymousTargetId);
+            this._targetManager.createTarget(WebInspector.UIString("Worker %s", workerId), connection, targetCreated);
         }
 
         /**
          * @param {!WebInspector.Target} target
          */
         function targetCreated(target)
         {
             if (data.inspectorConnected)
                 target.runtimeAgent().run();
         }
+    },
+
+    _onWorkersCleared: function()
+    {
+        this._lastAnonymousTargetId = 0;
     }
 }
 
 /**
  * @constructor
  * @extends {InspectorBackendClass.Connection}
  * @param {!WebInspector.Target} target
  * @param {number} workerId
  * @param {boolean} inspectorConnected
  * @param {!function(!InspectorBackendClass.Connection)} onConnectionReady
@@ skipping 48 matching lines @@
     _close: function()
     {
         this._target.workerManager.removeEventListener(WebInspector.WorkerManager.Events.MessageFromWorker, this._dispatchMessageFromWorker, this);
         this._target.workerManager.removeEventListener(WebInspector.WorkerManager.Events.WorkerRemoved, this._onWorkerRemoved, this);
         this._target.workerManager.removeEventListener(WebInspector.WorkerManager.Events.WorkersCleared, this._close, this);
         this.connectionClosed("worker_terminated");
     },
 
     __proto__: InspectorBackendClass.Connection.prototype
 }