Use SingleThreadTaskRunner instead of MessageLoopProxy in remoting/host.

remoting/host/host_user_interface.h

Index: remoting/host/host_user_interface.h
diff --git a/remoting/host/host_user_interface.h b/remoting/host/host_user_interface.h
index 942cd2a2b920241c0ec0e563464b7d18a5b991e2..ce509b8aaddba52dadbed0629842fc78645671a4 100644
--- a/remoting/host/host_user_interface.h
+++ b/remoting/host/host_user_interface.h
@@ -12,9 +12,12 @@
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
-#include "base/message_loop_proxy.h"
 #include "remoting/host/host_status_observer.h"
 
+namespace base {
+class SingleThreadTaskRunner;
+}  // namespace base
+
 namespace remoting {
 
 class ChromotingHost;
@@ -44,9 +47,8 @@ class HostUserInterface : public HostStatusObserver {
   }
   ChromotingHost* get_host() const { return host_; }
 
-  // Message loop accessors.
-  base::MessageLoopProxy* network_message_loop() const;
-  base::MessageLoopProxy* ui_message_loop() const;
+  base::SingleThreadTaskRunner* network_task_runner() const;
+  base::SingleThreadTaskRunner* ui_task_runner() const;
 
   // Invokes the session disconnect callback passed to Start().
   void DisconnectSession() const;