Add a file thread to the renderer process.

chrome/renderer/render_thread.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_RENDERER_RENDER_THREAD_H_
 #define CHROME_RENDERER_RENDER_THREAD_H_
 #pragma once
 
 #include <string>
 #include <vector>
@@ skipping 29 matching lines @@
 class URLPattern;
 class WebDatabaseObserverImpl;
 
 struct ContentSettings;
 struct RendererPreferences;
 struct ViewMsg_DOMStorageEvent_Params;
 struct ViewMsg_ExtensionExtentsUpdated_Params;
 struct ViewMsg_New_Params;
 struct WebPreferences;
 
+namespace base {
+class MessageLoopProxy;
+class Thread;
+}
+
 namespace IPC {
 struct ChannelHandle;
 }
 
 namespace WebKit {
 class WebStorageEventDispatcher;
 }
 
 // The RenderThreadBase is the minimal interface that a RenderView/Widget
 // expects from a render thread. The interface basically abstracts a way to send
@@ skipping 161 matching lines @@
   GpuChannelHost* GetGpuChannel();
 
   // Returns the extension ID that the given URL is a part of, or empty if
   // none. This includes web URLs that are part of an extension's web extent.
   // TODO(mpcomplete): this doesn't feel like it belongs here. Find a better
   // place.
   std::string GetExtensionIdByURL(const GURL& url);
 
   std::string GetExtensionIdByBrowseExtent(const GURL& url);
 
+  // Returns a MessageLoopProxy instance corresponding to the message loop
+  // of the thread on which file operations should be run. Must be called
+  // on the renderer's main thread.
+  scoped_refptr<base::MessageLoopProxy> GetFileThreadMessageLoopProxy();
+
  private:
   virtual void OnControlMessageReceived(const IPC::Message& msg);
 
   void Init();
 
   void OnUpdateVisitedLinks(base::SharedMemoryHandle table);
   void OnAddVisitedLinks(const VisitedLinkSlave::Fingerprints& fingerprints);
   void OnResetVisitedLinks();
   void OnSetZoomLevelForCurrentURL(const GURL& url, int zoom_level);
   void OnSetContentSettingsForCurrentURL(
@@ skipping 118 matching lines @@
   base::RepeatingTimer<RenderThread> forced_idle_timer_;
 
   // The channel from the renderer process to the GPU process.
   scoped_refptr<GpuChannelHost> gpu_channel_;
 
   // A list of extension web extents, which tells us which URLs belong to an
   // installed app.
   struct ExtensionInfo;
   std::vector<ExtensionInfo> extension_extents_;
 
+  // A lazily initiated thread on which file operations are run.
+  scoped_ptr<base::Thread> file_thread_;
+
   DISALLOW_COPY_AND_ASSIGN(RenderThread);
 };
 
 #endif  // CHROME_RENDERER_RENDER_THREAD_H_