Add MessagePipe interface. Use it in ChannelDispatcherBase.

remoting/protocol/audio_writer.cc

Index: remoting/protocol/audio_writer.cc
diff --git a/remoting/protocol/audio_writer.cc b/remoting/protocol/audio_writer.cc
index 3ab624b402a348f6e6f0fdaf0502d70a619c1367..be40f91717e51f159457dd8bd8926384a1cbb452 100644
--- a/remoting/protocol/audio_writer.cc
+++ b/remoting/protocol/audio_writer.cc
@@ -6,25 +6,22 @@
 
 #include "base/bind.h"
 #include "net/socket/stream_socket.h"
+#include "remoting/base/compound_buffer.h"
 #include "remoting/base/constants.h"
 #include "remoting/proto/audio.pb.h"
-#include "remoting/protocol/message_serialization.h"
+#include "remoting/protocol/message_pipe.h"
 #include "remoting/protocol/session.h"
 #include "remoting/protocol/session_config.h"
 
 namespace remoting {
 namespace protocol {
 
-AudioWriter::AudioWriter()
-    : ChannelDispatcherBase(kAudioChannelName) {
-}
-
-AudioWriter::~AudioWriter() {
-}
+AudioWriter::AudioWriter() : ChannelDispatcherBase(kAudioChannelName) {}
+AudioWriter::~AudioWriter() {}
 
 void AudioWriter::ProcessAudioPacket(scoped_ptr<AudioPacket> packet,
                                      const base::Closure& done) {
-  writer()->Write(SerializeAndFrameMessage(*packet), done);
+  message_pipe()->Send(packet.get(), done);
 }
 
 // static