Split ExtensionMessageFilter up into a UI thread part and an IO thread part.

extensions/browser/extension_function_dispatcher.h

 // 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.
 
 #ifndef EXTENSIONS_BROWSER_EXTENSION_FUNCTION_DISPATCHER_H_
 #define EXTENSIONS_BROWSER_EXTENSION_FUNCTION_DISPATCHER_H_
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/memory/weak_ptr.h"
 #include "extensions/browser/extension_function.h"
 #include "ipc/ipc_sender.h"
 
 struct ExtensionHostMsg_Request_Params;
 
 namespace content {
 class BrowserContext;
 class RenderFrameHost;
 class RenderViewHost;
 class WebContents;
 }
 
 namespace extensions {
 
 class Extension;
 class ExtensionAPI;
-class ExtensionMessageFilter;
 class InfoMap;
+class IOThreadExtensionMessageFilter;
 class ProcessMap;
 class WindowController;
 
 // A factory function for creating new ExtensionFunction instances.
 typedef ExtensionFunction* (*ExtensionFunctionFactory)();
 
 // ExtensionFunctionDispatcher receives requests to execute functions from
 // Chrome extensions running in a RenderViewHost and dispatches them to the
 // appropriate handler. It lives entirely on the UI thread.
 //
@@ skipping 37 matching lines @@
   // false if no such function was registered.
   static bool OverrideFunction(const std::string& name,
                                ExtensionFunctionFactory factory);
 
   // Dispatches an IO-thread extension function. Only used for specific
   // functions that must be handled on the IO-thread.
   static void DispatchOnIOThread(
       InfoMap* extension_info_map,
       void* profile_id,
       int render_process_id,
-      base::WeakPtr<ExtensionMessageFilter> ipc_sender,
+      base::WeakPtr<IOThreadExtensionMessageFilter> ipc_sender,
       int routing_id,
       const ExtensionHostMsg_Request_Params& params);
 
   // Public constructor. Callers must ensure that:
   // - |delegate| outlives this object.
   // - This object outlives any RenderViewHost's passed to created
   //   ExtensionFunctions.
   ExtensionFunctionDispatcher(content::BrowserContext* browser_context,
                               Delegate* delegate);
 
@@ skipping 63 matching lines @@
   // instance goes away, the corresponding entry in this map (if exists) will be
   // removed.
   typedef std::map<content::RenderViewHost*, UIThreadResponseCallbackWrapper*>
       UIThreadResponseCallbackWrapperMap;
   UIThreadResponseCallbackWrapperMap ui_thread_response_callback_wrappers_;
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_EXTENSION_FUNCTION_DISPATCHER_H_