Mojo: Make some attempts towards fixing remote message pipe closure.

mojo/system/local_message_pipe_endpoint.cc

Index: mojo/system/local_message_pipe_endpoint.cc
diff --git a/mojo/system/local_message_pipe_endpoint.cc b/mojo/system/local_message_pipe_endpoint.cc
index ece8e03190071f67e867f0ee01eee6ea106d5f40..b5b6bd022327b414e07f0c81cc4e05c181b3c9ea 100644
--- a/mojo/system/local_message_pipe_endpoint.cc
+++ b/mojo/system/local_message_pipe_endpoint.cc
@@ -27,13 +27,7 @@ MessagePipeEndpoint::Type LocalMessagePipeEndpoint::GetType() const {
   return kTypeLocal;
 }
 
-void LocalMessagePipeEndpoint::Close() {
-  DCHECK(is_open_);
-  is_open_ = false;
-  message_queue_.Clear();
-}
-
-void LocalMessagePipeEndpoint::OnPeerClose() {
+bool LocalMessagePipeEndpoint::OnPeerClose() {
   DCHECK(is_open_);
   DCHECK(is_peer_open_);
 
@@ -48,6 +42,8 @@ void LocalMessagePipeEndpoint::OnPeerClose() {
     waiter_list_.AwakeWaitersForStateChange(new_satisfied_flags,
                                             new_satisfiable_flags);
   }
+
+  return true;
 }
 
 void LocalMessagePipeEndpoint::EnqueueMessage(
@@ -63,6 +59,12 @@ void LocalMessagePipeEndpoint::EnqueueMessage(
   }
 }
 
+void LocalMessagePipeEndpoint::Close() {
+  DCHECK(is_open_);
+  is_open_ = false;
+  message_queue_.Clear();
+}
+
 void LocalMessagePipeEndpoint::CancelAllWaiters() {
   DCHECK(is_open_);
   waiter_list_.CancelAllWaiters();