Update ChannelReader to use AttachmentBroker.

ipc/handle_attachment_win.cc

 // Copyright 2015 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.
 
 #include "ipc/handle_attachment_win.h"
 
 #include <windows.h>
 
 namespace IPC {
 namespace internal {
 
 HandleAttachmentWin::HandleAttachmentWin(const HANDLE& handle)
     : handle_(handle) {
 }
 
 HandleAttachmentWin::HandleAttachmentWin(const WireFormat& wire_format)
-    : BrokerableAttachment(wire_format.attachment_id),
+    : BrokerableAttachment(wire_format.attachment_id, false),
       handle_(LongToHandle(wire_format.handle)) {
 }
 
+HandleAttachmentWin::HandleAttachmentWin(
+    const BrokerableAttachment::AttachmentId& id)
+    : BrokerableAttachment(id, true), handle_(INVALID_HANDLE_VALUE) {
+}
+
 HandleAttachmentWin::~HandleAttachmentWin() {
 }
 
 HandleAttachmentWin::BrokerableType HandleAttachmentWin::GetBrokerableType()
     const {
   return WIN_HANDLE;
 }
 
+void HandleAttachmentWin::PopulateWithAttachment(
+    const BrokerableAttachment* attachment) {
+  DCHECK(NeedsBrokering());
+  DCHECK(!attachment->NeedsBrokering());
+  DCHECK(GetIdentifier() == attachment->GetIdentifier());
+  DCHECK_EQ(GetBrokerableType(), attachment->GetBrokerableType());
+
+  const HandleAttachmentWin* handle_attachment =
+      static_cast<const HandleAttachmentWin*>(attachment);
+  handle_ = handle_attachment->handle_;
+  SetNeedsBrokering(false);
+}
+
 HandleAttachmentWin::WireFormat HandleAttachmentWin::GetWireFormat(
     const base::ProcessId& destination) const {
   WireFormat format;
   format.handle = HandleToLong(handle_);
   format.attachment_id = GetIdentifier();
   format.destination_process = destination;
   return format;
 }
 
 }  // namespace internal
 }  // namespace IPC