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

mojo/system/message_pipe.cc

Index: mojo/system/message_pipe.cc
diff --git a/mojo/system/message_pipe.cc b/mojo/system/message_pipe.cc
index d12e303c916d0396d2763bda3a9e9731d0076870..17cb5c07b844c41e0b9e1f8e9def975940c0f71a 100644
--- a/mojo/system/message_pipe.cc
+++ b/mojo/system/message_pipe.cc
@@ -75,7 +75,10 @@ void MessagePipe::Close(unsigned port) {
   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]) {
@@ -184,21 +187,6 @@ MojoResult MessagePipe::EnqueueMessage(unsigned port,
   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() {
 }