Add PluginMessageLoopProxy and use it for Host plugin UI thread.

remoting/host/chromoting_host_context.h

 // Copyright (c) 2011 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 REMOTING_HOST_CHROMOTING_HOST_CONTEXT_H_
 #define REMOTING_HOST_CHROMOTING_HOST_CONTEXT_H_
 
 #include <string>
 
 #include "base/callback.h"
 #include "base/gtest_prod_util.h"
 #include "base/threading/platform_thread.h"
 #include "base/threading/thread.h"
 #include "remoting/jingle_glue/jingle_thread.h"
 
 class Task;
 
 namespace tracked_objects {
 class Location;
 }
 
 namespace remoting {
 
 // A class that manages threads and running context for the chromoting host
 // process.  This class is virtual only for testing purposes (see below).
 class ChromotingHostContext {
  public:
-  typedef base::Callback<void(
-      const tracked_objects::Location& from_here,
-      const base::Closure& task)> UIThreadPostTaskFunction;
-
   // Create a context.
-  ChromotingHostContext();
+  ChromotingHostContext(base::MessageLoopProxy* ui_message_loop);
   virtual ~ChromotingHostContext();
 
   // TODO(ajwong): Move the Start/Stop methods out of this class. Then
   // create a static factory for construction, and destruction.  We
   // should be able to remove the need for virtual functions below with that
   // design, while preserving the relative simplicity of this API.
   virtual void Start();
   virtual void Stop();
 
   virtual JingleThread* jingle_thread();
 
+  virtual base::MessageLoopProxy* ui_message_loop();
   virtual MessageLoop* main_message_loop();
   virtual MessageLoop* encode_message_loop();
   virtual base::MessageLoopProxy* network_message_loop();
   virtual MessageLoop* desktop_message_loop();
 
-  // Must be called from the main GUI thread.
-  void SetUITaskPostFunction(const UIThreadPostTaskFunction& poster);
-
-  void PostTaskToUIThread(const tracked_objects::Location& from_here,
-                          const base::Closure& task);
-  void PostDelayedTaskToUIThread(const tracked_objects::Location& from_here,
-                                 const base::Closure& task,
-                                 int delay_ms);
-  bool IsUIThread() const;
-
  private:
   FRIEND_TEST_ALL_PREFIXES(ChromotingHostContextTest, StartAndStop);
 
   // A thread that hosts all network operations.
   JingleThread jingle_thread_;
   scoped_refptr<base::MessageLoopProxy> network_message_loop_;
 
   // A thread that hosts ChromotingHost and performs rate control.
   base::Thread main_thread_;
 
   // A thread that hosts all encode operations.
   base::Thread encode_thread_;
 
   // A thread that hosts desktop integration (capture, input injection, etc)
   // This is NOT a Chrome-style UI thread.
   base::Thread desktop_thread_;
 
-  UIThreadPostTaskFunction ui_poster_;
-  // This IS the main Chrome GUI thread that |ui_poster_| will post to.
-  base::PlatformThreadId ui_main_thread_id_;
-
+  scoped_refptr<base::MessageLoopProxy> ui_message_loop_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromotingHostContext);
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_HOST_CHROMOTING_HOST_CONTEXT_H_