Make the AppCacheDispatcherHost be a MessageFilter so that ResourceMessageFil...

chrome/browser/appcache/appcache_frontend_proxy.h

 // Copyright (c) 2010 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_APPCACHE_APPCACHE_FRONTEND_PROXY_H_
 #define CHROME_BROWSER_APPCACHE_APPCACHE_FRONTEND_PROXY_H_
 #pragma once
 
 #include <string>
 #include <vector>
 
 #include "ipc/ipc_message.h"
 #include "webkit/appcache/appcache_interfaces.h"
 
 // Sends appcache related messages to a child process.
 class AppCacheFrontendProxy : public appcache::AppCacheFrontend {
  public:
-  AppCacheFrontendProxy() : sender_(NULL) {}
-  void set_sender(IPC::Message::Sender* sender) { sender_ = sender; }
-  IPC::Message::Sender* sender() const { return sender_; }
+  explicit AppCacheFrontendProxy(IPC::Message::Sender* sender);
 
   // AppCacheFrontend methods
   virtual void OnCacheSelected(int host_id, const appcache::AppCacheInfo& info);
   virtual void OnStatusChanged(const std::vector<int>& host_ids,
                                appcache::Status status);
   virtual void OnEventRaised(const std::vector<int>& host_ids,
                              appcache::EventID event_id);
   virtual void OnProgressEventRaised(const std::vector<int>& host_ids,
                                      const GURL& url,
                                      int num_total, int num_complete);
   virtual void OnErrorEventRaised(const std::vector<int>& host_ids,
                                   const std::string& message);
   virtual void OnLogMessage(int host_id, appcache::LogLevel log_level,
                             const std::string& message);
   virtual void OnContentBlocked(int host_id,
                                 const GURL& manifest_url);
 
  private:
   IPC::Message::Sender* sender_;
 };
 
 #endif  // CHROME_BROWSER_APPCACHE_APPCACHE_FRONTEND_PROXY_H_