IPC: Make ChannelReader inherit from SupportsAttachmentBrokering.

ipc/ipc_channel_nacl.h

 // Copyright (c) 2012 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_NACL_H_
 #define IPC_IPC_CHANNEL_NACL_H_
 
 #include <deque>
 #include <string>
 
@@ skipping 19 matching lines @@
 // We don't need to worry about complicated set up and READWRITE mode for
 // sharing handles. We also currently do not support passing file descriptors or
 // named pipes, and we use background threads to emulate signaling when we can
 // read or write without blocking.
 class ChannelNacl : public Channel,
                     public internal::ChannelReader {
  public:
   // Mirror methods of Channel, see ipc_channel.h for description.
   ChannelNacl(const IPC::ChannelHandle& channel_handle,
               Mode mode,
-              Listener* listener);
+              Listener* listener,
+              AttachmentBroker* broker);
   ~ChannelNacl() override;
 
   // Channel implementation.
   base::ProcessId GetPeerPID() const override;
   base::ProcessId GetSelfPID() const override;
   bool Connect() override;
   void Close() override;
   bool Send(Message* message) override;
+  AttachmentBroker* GetAttachmentBroker() override;
 
   // Posted to the main thread by ReaderThreadRunner.
   void DidRecvMsg(scoped_ptr<MessageContents> contents);
   void ReadDidFail();
 
  private:
   class ReaderThreadRunner;
 
   bool CreatePipe(const IPC::ChannelHandle& channel_handle);
   bool ProcessOutgoingMessages();
@@ skipping 48 matching lines @@
   // don't change to something like std::deque<> without changing the
   // implementation!
   std::vector<int> input_fds_;
 
   // This queue is used when a message is sent prior to Connect having been
   // called. Normally after we're connected, the queue is empty.
   std::deque<linked_ptr<Message> > output_queue_;
 
   base::WeakPtrFactory<ChannelNacl> weak_ptr_factory_;
 
+  // |broker_| must outlive this instance.

[Tom Sepez, 2015/06/16 16:36:44]

nit: maybe move this comment to the ctor, where the caller will actually pass in
the broker.

[erikchen, 2015/06/16 17:36:47]

I kept the comment here, and added a similar comment to the constructor. 

+  AttachmentBroker* broker_;

[Will Harris, 2015/06/16 13:06:04]

where will this object be created and how will the lifetime be managed, all the
code in this CL passes nullptr so hard to determine.

[erikchen, 2015/06/16 17:36:47]

The short answer is: Each process is responsible for ensuring the lifetime of
this object, and in general this is one of the last objects to be deleted when a
process is destroyed.

The long answer is: See this CL: https://codereview.chromium.org/1184523003/ for
more context. The CL I referenced is not going to go out for review (since it
touches ~50 files), and this CL that you're currently reviewing is a strict
subset of this CL.

+
   DISALLOW_IMPLICIT_CONSTRUCTORS(ChannelNacl);
 };
 
 }  // namespace IPC
 
 #endif  // IPC_IPC_CHANNEL_NACL_H_