Separate out IPC::Message::Sender and channel::Listener into a separate class.

ipc/ipc_sync_message_filter.h

Index: ipc/ipc_sync_message_filter.h
diff --git a/ipc/ipc_sync_message_filter.h b/ipc/ipc_sync_message_filter.h
index a4c27a269a316b963180afa549064f2519126037..b551f16bcc9ffc906c08be5880d8b35489616b89 100644
--- a/ipc/ipc_sync_message_filter.h
+++ b/ipc/ipc_sync_message_filter.h
@@ -27,11 +27,11 @@ namespace IPC {
 // receiving messages while waiting for a response.  Note that this object can
 // be used to send simultaneous synchronous messages from different threads.
 class IPC_EXPORT SyncMessageFilter : public ChannelProxy::MessageFilter,
-                                     public Message::Sender {
+                                     public Sender {
  public:
   explicit SyncMessageFilter(base::WaitableEvent* shutdown_event);
 
-  // Message::Sender implementation.
+  // MessageSender implementation.
   virtual bool Send(Message* message) OVERRIDE;
 
   // ChannelProxy::MessageFilter implementation.