Make IPC::Channel::Listener:OnMessageReceived have a return value indicating ...

ipc/ipc_channel.h

 // Copyright (c) 2010 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 IPC_IPC_CHANNEL_H_
 #define IPC_IPC_CHANNEL_H_
 #pragma once
 
 #include "base/compiler_specific.h"
 #include "ipc/ipc_channel_handle.h"
@@ skipping 21 matching lines @@
 class Channel : public Message::Sender {
   // Security tests need access to the pipe handle.
   friend class ChannelTest;
 
  public:
   // Implemented by consumers of a Channel to receive messages.
   class Listener {
    public:
     virtual ~Listener() {}
 
-    // Called when a message is received.
-    virtual void OnMessageReceived(const Message& message) = 0;
+    // Called when a message is received.  Returns true iff the message was
+    // handled.
+    virtual bool OnMessageReceived(const Message& message) = 0;
 
     // Called when the channel is connected and we have received the internal
     // Hello message from the peer.
     virtual void OnChannelConnected(int32 peer_pid) {}
 
     // Called when an error is detected that causes the channel to close.
     // This method is not called when a channel is closed normally.
     virtual void OnChannelError() {}
 
 #if defined(OS_POSIX)
@@ skipping 113 matching lines @@
     HELLO_MESSAGE_TYPE = kuint16max  // Maximum value of message type (uint16),
                                      // to avoid conflicting with normal
                                      // message types, which are enumeration
                                      // constants starting from 0.
   };
 };
 
 }  // namespace IPC
 
 #endif  // IPC_IPC_CHANNEL_H_