[DevTools] Remove Common.Event.target field.

third_party/WebKit/Source/devtools/front_end/persistence/DefaultMapping.js

 // Copyright 2016 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.
 /**
  * @unrestricted
  */
 Persistence.DefaultMapping = class {
   /**
    * @param {!Workspace.Workspace} workspace
    * @param {!Workspace.FileSystemMapping} fileSystemMapping
@@ skipping 109 matching lines @@
     binding.fileSystem.removeEventListener(
         Workspace.UISourceCode.Events.TitleChanged, this._onFileSystemUISourceCodeRenamed, this);
 
     this._onBindingRemoved.call(null, binding);
   }
 
   /**
    * @param {!Common.Event} event
    */
   _onFileSystemUISourceCodeRenamed(event) {
-    var uiSourceCode = /** @type {!Workspace.UISourceCode} */ (event.target);
+    var uiSourceCode = /** @type {!Workspace.UISourceCode} */ (event.data);
     var binding = uiSourceCode[Persistence.DefaultMapping._binding];
     this._unbind(binding.network);
     this._bind(binding.network);
   }
 
   dispose() {
     Common.EventTarget.removeEventListeners(this._eventListeners);
   }
 };
 
 Persistence.DefaultMapping._binding = Symbol('DefaultMapping.Binding');