[chrome/renderer/media] Replace MessageLoopProxy usage with ThreadTaskRunnerHandle

chrome/renderer/media/cast_ipc_dispatcher.cc

Index: chrome/renderer/media/cast_ipc_dispatcher.cc
diff --git a/chrome/renderer/media/cast_ipc_dispatcher.cc b/chrome/renderer/media/cast_ipc_dispatcher.cc
index a88103db8cc523aeaafc2487d8d66c383a60e44c..8bf4076f1015c314c8502aacd1fcef05b7d0c2a8 100644
--- a/chrome/renderer/media/cast_ipc_dispatcher.cc
+++ b/chrome/renderer/media/cast_ipc_dispatcher.cc
@@ -4,6 +4,7 @@
 
 #include "chrome/renderer/media/cast_ipc_dispatcher.h"
 
+#include "base/single_thread_task_runner.h"
 #include "chrome/common/cast_messages.h"
 #include "chrome/renderer/media/cast_transport_sender_ipc.h"
 #include "ipc/ipc_message_macros.h"
@@ -11,7 +12,7 @@
 CastIPCDispatcher* CastIPCDispatcher::global_instance_ = NULL;
 
 CastIPCDispatcher::CastIPCDispatcher(
-    const scoped_refptr<base::MessageLoopProxy>& io_message_loop)
+    const scoped_refptr<base::SingleThreadTaskRunner>& io_message_loop)
     : sender_(NULL),
       io_message_loop_(io_message_loop) {
   DCHECK(io_message_loop_.get());