Add support for passing an arbitrary parameter to an IPC message handler. The motivation is for Web…

content/renderer/browser_plugin/browser_plugin_manager_impl.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 CONTENT_RENDERER_BROWSER_PLUGIN_BROWSER_PLUGIN_MANAGER_IMPL_H_
 #define CONTENT_RENDERER_BROWSER_PLUGIN_BROWSER_PLUGIN_MANAGER_IMPL_H_
 
 #include <map>
 
 #include "content/renderer/browser_plugin/browser_plugin_manager.h"
@@ skipping 20 matching lines @@
   // IPC::Sender implementation.
   virtual bool Send(IPC::Message* msg) OVERRIDE;
 
   // RenderViewObserver override. Call on render thread.
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
   virtual void DidCommitCompositorFrame() OVERRIDE;
 
  private:
   virtual ~BrowserPluginManagerImpl();
 
-  void OnAllocateInstanceIDACK(const IPC::Message& message,
-                               int request_id,
+  void OnAllocateInstanceIDACK(int request_id,
                                int guest_instance_id);
 
   int request_id_counter_;
   typedef std::map<int, const base::WeakPtr<BrowserPlugin> > InstanceIDMap;
   InstanceIDMap pending_allocate_guest_instance_id_requests_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserPluginManagerImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_BROWSER_PLUGIN_BROWSER_PLUGIN_MANAGER_IMPL_H_