Have MessagePort use Oilpan-based weak pointers.

third_party/WebKit/Source/core/dom/DocumentInit.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
@@ skipping 16 matching lines @@
 
 #ifndef DocumentInit_h
 #define DocumentInit_h
 
 #include "core/CoreExport.h"
 #include "core/dom/SandboxFlags.h"
 #include "core/dom/SecurityContext.h"
 #include "core/dom/custom/V0CustomElementRegistrationContext.h"
 #include "platform/heap/Handle.h"
 #include "platform/weborigin/KURL.h"
-#include "wtf/WeakPtr.h"
 
 namespace blink {
 
 class Document;
 class LocalFrame;
 class HTMLImportsController;
 class Settings;
 
 class CORE_EXPORT DocumentInit final {
     STACK_ALLOCATED();
@@ skipping 50 matching lines @@
     // won't be blown away when the network load commits. To make that happen, we
     // "securely transition" the existing LocalDOMWindow to the Document that results from
     // the network load. See also SecurityContext::isSecureTransitionTo.
     // FIXME: This is for DocumentWriter creation, not for one of Document.
     bool m_shouldReuseDefaultView;
 };
 
 } // namespace blink
 
 #endif // DocumentInit_h