Refactor the socket API to remove onEvent callback in socket.create() function.

chrome/browser/extensions/api/api_function.h

 // Copyright (c) 2012 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.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_API_API_FUNCTION_H_
 #define CHROME_BROWSER_EXTENSIONS_API_API_FUNCTION_H_
 #pragma once
 
 #include "chrome/browser/extensions/extension_function.h"
 #include "chrome/browser/extensions/api/api_resource.h"
 
 class ExtensionService;
 
 namespace extensions {
 
 class APIResourceController;
 class APIResourceEventNotifier;
 
 // AsyncIOAPIFunction provides convenient thread management for APIs that
 // need to do essentially all their work on the IO thread.
 class AsyncIOAPIFunction : public AsyncExtensionFunction {
  protected:
   virtual ~AsyncIOAPIFunction() {}
 
   // Set up for work (e.g., validate arguments). Guaranteed to happen on UI
   // thread.
   virtual bool Prepare() = 0;
 
   // Do actual work. Guaranteed to happen on IO thread.
-  virtual void Work() = 0;
+  virtual void Work();
+
+  // Start the asynchronous work. Guraranteed to happen on IO thread.
+  virtual void AsyncWorkStart();
+
+  // Notify AsyncIOAPIFunction that the work is completed
+  void AsyncWorkCompleted();
 
   // Respond. Guaranteed to happen on UI thread.
   virtual bool Respond() = 0;
 
   // Looks for a kSrcId key that might have been added to a create method's
   // options object.
   int ExtractSrcId(size_t argument_position);
 
   // Utility.
   APIResourceEventNotifier* CreateEventNotifier(int src_id);
 
   // Access to the controller singleton.
   APIResourceController* controller();
 
   // ExtensionFunction:
   virtual bool RunImpl() OVERRIDE;
 
  private:
   void WorkOnIOThread();
   void RespondOnUIThread();
 
   ExtensionService* extension_service_;
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_API_FUNCTION_H_