Add PluginMessageLoopProxy and use it for Host plugin UI thread.

remoting/host/simple_host_process.cc

 // 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.
 //
 // This is an application of a minimal host process in a Chromoting
 // system. It serves the purpose of gluing different pieces together
 // to make a functional host process for testing.
 //
 // It peforms the following functionality:
 // 1. Connect to the GTalk network and register the machine as a host.
@@ skipping 86 matching lines @@
       : fake_(false),
         is_it2me_(false) {
   }
 
   int Run() {
     // |message_loop| is declared early so that any code we call into which
     // requires a current message-loop won't complain.
     // It needs to be a UI message loop to keep runloops spinning on the Mac.
     MessageLoop message_loop(MessageLoop::TYPE_UI);
 
-    remoting::ChromotingHostContext context;
-    // static_cast needed to resolve overloaded PostTask member-function.
-    context.SetUITaskPostFunction(base::Bind(
-        static_cast<void(MessageLoop::*)(
-            const tracked_objects::Location&,
-            const base::Closure&)>(&MessageLoop::PostTask),
-        base::Unretained(&message_loop)));
+    remoting::ChromotingHostContext context(
+        base::MessageLoopProxy::CreateForCurrentThread());
     context.Start();
 
     base::Thread file_io_thread("FileIO");
     file_io_thread.Start();
 
     FilePath config_path = GetConfigPath();
     scoped_refptr<remoting::JsonHostConfig> config =
         new remoting::JsonHostConfig(
             config_path, file_io_thread.message_loop_proxy());
     if (!config->Read()) {
@@ skipping 196 matching lines @@
       LOG(ERROR) << "Unknown video codec: " << video_codec;
       return 1;
     }
     config->mutable_video_configs()->push_back(ChannelConfig(
         transport, remoting::protocol::kDefaultStreamVersion, codec));
     simple_host.set_protocol_config(config.release());
   }
 
   return simple_host.Run();
 }