ipc: Use a global for the process's attachment broker.

ipc/ipc_channel_win.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_WIN_H_
 #define IPC_IPC_CHANNEL_WIN_H_
 
 #include "ipc/ipc_channel.h"
 
 #include <stdint.h>
@@ skipping 14 matching lines @@
 namespace IPC {
 
 class ChannelWin : public Channel,
                    public internal::ChannelReader,
                    public base::MessageLoopForIO::IOHandler {
  public:
   // Mirror methods of Channel, see ipc_channel.h for description.
   // |broker| must outlive the newly created object.
   ChannelWin(const IPC::ChannelHandle& channel_handle,
              Mode mode,
-             Listener* listener,
-             AttachmentBroker* broker);
+             Listener* listener);
   ~ChannelWin() override;
 
   // Channel implementation
   bool Connect() override;
   void Close() override;
   bool Send(Message* message) override;
   AttachmentBroker* GetAttachmentBroker() override;
   base::ProcessId GetPeerPID() const override;
   base::ProcessId GetSelfPID() const override;
 
@@ skipping 79 matching lines @@
   uint32_t debug_flags_;
 
   // This is a unique per-channel value used to authenticate the client end of
   // a connection. If the value is non-zero, the client passes it in the hello
   // and the host validates. (We don't send the zero value fto preserve IPC
   // compatability with existing clients that don't validate the channel.)
   int32_t client_secret_;
 
   scoped_ptr<base::ThreadChecker> thread_check_;
 
-  // |broker_| must outlive this instance.
-  AttachmentBroker* broker_;
-
   base::WeakPtrFactory<ChannelWin> weak_factory_;
   DISALLOW_COPY_AND_ASSIGN(ChannelWin);
 };
 
 }  // namespace IPC
 
 #endif  // IPC_IPC_CHANNEL_WIN_H_