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

mojo/system/local_message_pipe_endpoint.h

Index: mojo/system/local_message_pipe_endpoint.h
diff --git a/mojo/system/local_message_pipe_endpoint.h b/mojo/system/local_message_pipe_endpoint.h
index 9e200f16f7e04d86cba5cb4c0bd261d19e3350b8..963188f1df32642ff6f7c5aa63ba3b3d882fe086 100644
--- a/mojo/system/local_message_pipe_endpoint.h
+++ b/mojo/system/local_message_pipe_endpoint.h
@@ -24,12 +24,12 @@ class MOJO_SYSTEM_IMPL_EXPORT LocalMessagePipeEndpoint
 
   // |MessagePipeEndpoint| implementation:
   virtual Type GetType() const OVERRIDE;
-  virtual void Close() OVERRIDE;
-  virtual void OnPeerClose() OVERRIDE;
+  virtual bool OnPeerClose() OVERRIDE;
   virtual void EnqueueMessage(scoped_ptr<MessageInTransit> message) OVERRIDE;
 
   // There's a dispatcher for |LocalMessagePipeEndpoint|s, so we have to
   // implement/override these:
+  virtual void Close() OVERRIDE;
   virtual void CancelAllWaiters() OVERRIDE;
   virtual MojoResult ReadMessage(
       void* bytes, uint32_t* num_bytes,