Mojo: Remove knowledge of Channel, etc. from ProxyMessagePipeEndpoint.

mojo/system/channel.cc

Index: mojo/system/channel.cc
diff --git a/mojo/system/channel.cc b/mojo/system/channel.cc
index 3a87b01401808981ea98ac9ad42974abbe112a06..98dc511668e31f02987d84c3dab5b7534b1afe10 100644
--- a/mojo/system/channel.cc
+++ b/mojo/system/channel.cc
@@ -119,7 +119,7 @@ MessageInTransit::EndpointId Channel::AttachMessagePipeEndpoint(
 
   endpoint->AttachToChannel(this, local_id);
   // This might fail if that port got an |OnPeerClose()| before attaching.
-  if (message_pipe->Attach(port, endpoint.get(), this, local_id))
+  if (message_pipe->Attach(port, endpoint.get()))
     return local_id;
 
   // Note: If it failed, quite possibly the endpoint info was removed from that
@@ -180,7 +180,7 @@ bool Channel::RunMessagePipeEndpoint(MessageInTransit::EndpointId local_id,
   // running when we're here due to |kSubtypeChannelRunMessagePipeEndpoint|).
   endpoint->Run(remote_id);
   // TODO(vtl): Get rid of this.
-  message_pipe->Run(port, remote_id);
+  message_pipe->Run(port);
   return true;
 }