Revert 97050 - Add PluginMessageLoopProxy and use it for Host plugin UI thread.

remoting/host/chromoting_host_context.h

Index: remoting/host/chromoting_host_context.h
===================================================================
--- remoting/host/chromoting_host_context.h	(revision 97052)
+++ remoting/host/chromoting_host_context.h	(working copy)
@@ -25,8 +25,12 @@
 // 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(base::MessageLoopProxy* ui_message_loop);
+  ChromotingHostContext();
   virtual ~ChromotingHostContext();
 
   // TODO(ajwong): Move the Start/Stop methods out of this class. Then
@@ -38,12 +42,21 @@
 
   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);
 
@@ -60,8 +73,11 @@
   // This is NOT a Chrome-style UI thread.
   base::Thread desktop_thread_;
 
-  scoped_refptr<base::MessageLoopProxy> ui_message_loop_;
+  UIThreadPostTaskFunction ui_poster_;
+  // This IS the main Chrome GUI thread that |ui_poster_| will post to.
+  base::PlatformThreadId ui_main_thread_id_;
 
+
   DISALLOW_COPY_AND_ASSIGN(ChromotingHostContext);
 };