DevTools: Refactor nits in DebuggerModel event dispatching.

Source/devtools/front_end/sources/AsyncOperationsSidebarPane.js

 // Copyright 2015 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.NativeBreakpointsSidebarPane}
  * @implements {WebInspector.TargetManager.Observer}
  */
 WebInspector.AsyncOperationsSidebarPane = function()
@@ skipping 162 matching lines @@
         this.expand();
         if (this._target)
             this._target.debuggerAgent().flushAsyncOperationEvents();
     },
 
     /**
      * @param {!WebInspector.Event} event
      */
     _onAsyncOperationStarted: function(event)
     {
-        var target = /** @type {!WebInspector.Target} */ (event.data.target);
-        var operation = /** @type {!DebuggerAgent.AsyncOperation} */ (event.data.operation);
+        var target = /** @type {!WebInspector.Target} */ (event.target.target());
+        var operation = /** @type {!DebuggerAgent.AsyncOperation} */ (event.data);
 
         var operationsMap = this._asyncOperationsByTarget.get(target);
         if (!operationsMap) {
             operationsMap = new Map();
             this._asyncOperationsByTarget.set(target, operationsMap)
         }
         operationsMap.set(operation.id, operation);
 
         if (this._target === target)
             this._createAsyncOperationItem(operation);
     },
 
     /**
      * @param {!WebInspector.Event} event
      */
     _onAsyncOperationCompleted: function(event)
     {
-        var target = /** @type {!WebInspector.Target} */ (event.data.target);
-        var operationId = /** @type {number} */ (event.data.operationId);
+        var target = /** @type {!WebInspector.Target} */ (event.target.target());
+        var operationId = /** @type {number} */ (event.data);
 
         var operationsMap = this._asyncOperationsByTarget.get(target);
         if (operationsMap)
             operationsMap.delete(operationId);
 
         if (this._target === target) {
             var element = this._operationIdToElement.get(operationId);
             if (element)
                 this.removeListElement(element);
             this._operationIdToElement.delete(operationId);
@@ skipping 94 matching lines @@
             return null;
         var operationId = anchor[WebInspector.AsyncOperationsSidebarPane._operationIdSymbol];
         var operation = operationId && asyncOperations.get(operationId);
         if (!operation || !operation.stackTrace)
             return null;
         return operation;
     },
 
     __proto__: WebInspector.NativeBreakpointsSidebarPane.prototype
 }