AppCache: Use a dedicated thread for the disk cache.

webkit/appcache/appcache_thread.h

 // Copyright (c) 2009 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 WEBKIT_APPCACHE_APPCACHE_THREAD_H_
 #define WEBKIT_APPCACHE_APPCACHE_THREAD_H_
 
 #include "base/task.h"
 
 namespace tracked_objects {
 class Location;
 }
 
-class MessageLoop;
-
 namespace appcache {
 
 // The appcache system uses two threads, an IO thread and a DB thread.
 // It does not create these threads, the embedder is responsible for
 // providing them to the appcache library by providing a concrete
 // implementation of the PostTask and CurrentlyOn methods declared here,
 // and by calling the Init method prior to using the appcache library.
-// The disk_cache also requires the embedder to provide a thread message
-// loop.
 class AppCacheThread {
  public:
-  static void Init(int db, int io, MessageLoop* disk_cache_thread) {
+  static void Init(int db, int io) {
     db_ = db;
     io_ = io;
-    disk_cache_thread_ = disk_cache_thread;
   }
   static int db() { return db_; }
   static int io() { return io_; }
-  static MessageLoop* disk_cache_thread() { return disk_cache_thread_; }
 
   static bool PostTask(int id,
                        const tracked_objects::Location& from_here,
                        Task* task);
   static bool CurrentlyOn(int id);
 
   template <class T>
   static bool DeleteSoon(int id,
                          const tracked_objects::Location& from_here,
                          T* object) {
     return PostTask(id, from_here, new DeleteTask<T>(object));
   }
 
  private:
   AppCacheThread();
   ~AppCacheThread();
 
   static int db_;
   static int io_;
-  static MessageLoop* disk_cache_thread_;
 };
 
 }  // namespace appcache
 
 #endif  // WEBKIT_APPCACHE_APPCACHE_THREAD_H_