Don't depend on MessageLoopProxy in remoting protocol code.

remoting/protocol/protobuf_video_writer.h

Index: remoting/protocol/protobuf_video_writer.h
diff --git a/remoting/protocol/protobuf_video_writer.h b/remoting/protocol/protobuf_video_writer.h
index d3545a8a7ef83b6543ad416065bd9b12439b51b3..c5fa3213a76d0f64466b4c48ab9ac4628d37f551 100644
--- a/remoting/protocol/protobuf_video_writer.h
+++ b/remoting/protocol/protobuf_video_writer.h
@@ -13,10 +13,6 @@
 #include "remoting/protocol/buffered_socket_writer.h"
 #include "remoting/protocol/video_writer.h"
 
-namespace base {
-class MessageLoopProxy;
-}  // namespace base
-
 namespace net {
 class StreamSocket;
 }  // namespace net
@@ -28,7 +24,7 @@ class Session;
 
 class ProtobufVideoWriter : public VideoWriter {
  public:
-  ProtobufVideoWriter(base::MessageLoopProxy* message_loop);
+  ProtobufVideoWriter();
   virtual ~ProtobufVideoWriter();
 
   // VideoWriter interface.