Simplify message parsing.

remoting/protocol/host_video_dispatcher.cc

Index: remoting/protocol/host_video_dispatcher.cc
diff --git a/remoting/protocol/host_video_dispatcher.cc b/remoting/protocol/host_video_dispatcher.cc
index 0d7c0de53997277767537159cf5f6165dc823b23..ca9b63436d493ac7fb32719b8af1e236a2628bac 100644
--- a/remoting/protocol/host_video_dispatcher.cc
+++ b/remoting/protocol/host_video_dispatcher.cc
@@ -9,6 +9,7 @@
 #include "base/bind.h"
 #include "net/socket/stream_socket.h"
 #include "remoting/base/constants.h"
+#include "remoting/proto/video.pb.h"
 #include "remoting/protocol/message_serialization.h"
 #include "remoting/protocol/video_feedback_stub.h"
 
@@ -16,12 +17,7 @@ namespace remoting {
 namespace protocol {
 
 HostVideoDispatcher::HostVideoDispatcher()
-    : ChannelDispatcherBase(kVideoChannelName),
-      parser_(
-          base::Bind(&HostVideoDispatcher::OnVideoAck, base::Unretained(this)),
-          reader()),
-      video_feedback_stub_(nullptr) {}
-
+    : ChannelDispatcherBase(kVideoChannelName) {}
 HostVideoDispatcher::~HostVideoDispatcher() {}
 
 void HostVideoDispatcher::ProcessVideoPacket(scoped_ptr<VideoPacket> packet,
@@ -29,7 +25,11 @@ void HostVideoDispatcher::ProcessVideoPacket(scoped_ptr<VideoPacket> packet,
   writer()->Write(SerializeAndFrameMessage(*packet), done);
 }
 
-void HostVideoDispatcher::OnVideoAck(scoped_ptr<VideoAck> ack) {
+void HostVideoDispatcher::OnIncomingMessage(
+    scoped_ptr<CompoundBuffer> message) {
+  scoped_ptr<VideoAck> ack = ParseMessage<VideoAck>(message.get());
+  if (!ack)
+    return;
   if (video_feedback_stub_)
     video_feedback_stub_->ProcessVideoAck(std::move(ack));
 }