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

mojo/system/message_pipe_endpoint.h

 // 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.
 
 #ifndef MOJO_SYSTEM_MESSAGE_PIPE_ENDPOINT_H_
 #define MOJO_SYSTEM_MESSAGE_PIPE_ENDPOINT_H_
 
 #include <stdint.h>
 
 #include <vector>
@@ skipping 24 matching lines @@
  public:
   virtual ~MessagePipeEndpoint() {}
 
   enum Type {
     kTypeLocal,
     kTypeProxy
   };
   virtual Type GetType() const = 0;
 
   // All implementations must implement these.
-  virtual void Close() = 0;
-  virtual void OnPeerClose() = 0;
+  // Returns false if the endpoint should be closed and destroyed, else true.
+  virtual bool OnPeerClose() = 0;
   // Implements |MessagePipe::EnqueueMessage()|. The major differences are that:
   //  a) Dispatchers have been vetted and cloned/attached to the message.
   //  b) At this point, we cannot report failure (if, e.g., a channel is torn
   //     down at this point, we should silently swallow the message).
   virtual void EnqueueMessage(scoped_ptr<MessageInTransit> message) = 0;
 
   // Implementations must override these if they represent a local endpoint,
   // i.e., one for which there's a |MessagePipeDispatcher| (and thus a handle).
   // An implementation for a proxy endpoint (for which there's no dispatcher)
   // needs not override these methods, since they should never be called.
   //
   // These methods implement the methods of the same name in |MessagePipe|,
   // though |MessagePipe|'s implementation may have to do a little more if the
   // operation involves both endpoints.
+  virtual void Close();
   virtual void CancelAllWaiters();
   virtual MojoResult ReadMessage(
       void* bytes, uint32_t* num_bytes,
       std::vector<scoped_refptr<Dispatcher> >* dispatchers,
       uint32_t* num_dispatchers,
       MojoReadMessageFlags flags);
   virtual MojoResult AddWaiter(Waiter* waiter,
                                MojoWaitFlags flags,
                                MojoResult wake_result);
   virtual void RemoveWaiter(Waiter* waiter);
 
   // Implementations must override these if they represent a proxy endpoint. An
   // implementation for a local endpoint needs not override these methods, since
   // they should never be called.
   virtual void Attach(scoped_refptr<Channel> channel,
                       MessageInTransit::EndpointId local_id);
-  virtual void Run(MessageInTransit::EndpointId remote_id);
+  // Returns false if the endpoint should be closed and destroyed, else true.
+  virtual bool Run(MessageInTransit::EndpointId remote_id);
+  virtual void OnRemove();
 
  protected:
   MessagePipeEndpoint() {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MessagePipeEndpoint);
 };
 
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_SYSTEM_MESSAGE_PIPE_ENDPOINT_H_