Mojo: Remove MessagePipe::OnRemove(); instead just use MessagePipe::Close().

mojo/system/message_pipe.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "mojo/system/message_pipe.h"
 
 #include "base/logging.h"
 #include "mojo/system/channel_endpoint.h"
 #include "mojo/system/local_message_pipe_endpoint.h"
 #include "mojo/system/message_in_transit.h"
@@ skipping 57 matching lines @@
   DCHECK(endpoints_[port]);
   endpoints_[port]->CancelAllWaiters();
 }
 
 void MessagePipe::Close(unsigned port) {
   DCHECK(port == 0 || port == 1);
 
   unsigned destination_port = GetPeerPort(port);
 
   base::AutoLock locker(lock_);
-  DCHECK(endpoints_[port]);
+  // The endpoint's |OnPeerClose()| may have been called first and returned
+  // false, which would have resulted in its destruction.
+  if (!endpoints_[port])
+    return;
 
   endpoints_[port]->Close();
   if (endpoints_[destination_port]) {
     if (!endpoints_[destination_port]->OnPeerClose())
       endpoints_[destination_port].reset();
   }
   endpoints_[port].reset();
 }
 
 // TODO(vtl): Handle flags.
@@ skipping 88 matching lines @@
   old_endpoint->Close();
 
   return channel_endpoint;
 }
 
 MojoResult MessagePipe::EnqueueMessage(unsigned port,
                                        scoped_ptr<MessageInTransit> message) {
   return EnqueueMessageInternal(port, message.Pass(), nullptr);
 }
 
-void MessagePipe::OnRemove(unsigned port) {
-  unsigned destination_port = GetPeerPort(port);
-
-  base::AutoLock locker(lock_);
-  // A |OnPeerClose()| can come in first, before |OnRemove()| gets called.
-  if (!endpoints_[port])
-    return;
-
-  if (endpoints_[destination_port]) {
-    if (!endpoints_[destination_port]->OnPeerClose())
-      endpoints_[destination_port].reset();
-  }
-  endpoints_[port].reset();
-}
-
 MessagePipe::MessagePipe() {
 }
 
 MessagePipe::~MessagePipe() {
   // Owned by the dispatchers. The owning dispatchers should only release us via
   // their |Close()| method, which should inform us of being closed via our
   // |Close()|. Thus these should already be null.
   DCHECK(!endpoints_[0]);
   DCHECK(!endpoints_[1]);
 }
@@ skipping 77 matching lines @@
 MojoResult MessagePipe::HandleControlMessage(
     unsigned /*port*/,
     scoped_ptr<MessageInTransit> message) {
   LOG(WARNING) << "Unrecognized MessagePipe control message subtype "
                << message->subtype();
   return MOJO_RESULT_UNKNOWN;
 }
 
 }  // namespace system
 }  // namespace mojo