Mojo: Give ChannelEndpoint the remote ID and ProxyMessagePipeEndpoint the ChannelEndpoint.

mojo/system/message_pipe.h

Index: mojo/system/message_pipe.h
diff --git a/mojo/system/message_pipe.h b/mojo/system/message_pipe.h
index da171e2724c727a6deb3fef19cd0c440c4dfb627..3bc57a55110e898fe50bf60cd1bfda6fdcd10324 100644
--- a/mojo/system/message_pipe.h
+++ b/mojo/system/message_pipe.h
@@ -26,6 +26,7 @@ namespace mojo {
 namespace system {
 
 class Channel;
+class ChannelEndpoint;
 class Waiter;
 
 // |MessagePipe| is the secondary object implementing a message pipe (see the
@@ -96,7 +97,8 @@ class MOJO_SYSTEM_IMPL_EXPORT MessagePipe
 
   // These are used by |Channel|.
   bool Attach(unsigned port,
-              scoped_refptr<Channel> channel,
+              ChannelEndpoint* channel_endpoint,
+              Channel* channel,
               MessageInTransit::EndpointId local_id);
   void Run(unsigned port, MessageInTransit::EndpointId remote_id);
   void OnRemove(unsigned port);