Have MessagePort use Oilpan-based weak pointers.

third_party/WebKit/Source/core/workers/WorkerThread.cpp

 /*
  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 29 matching lines @@
 #include "platform/ThreadSafeFunctional.h"
 #include "platform/WaitableEvent.h"
 #include "platform/WebThreadSupportingGC.h"
 #include "platform/heap/SafePoint.h"
 #include "platform/heap/ThreadState.h"
 #include "platform/weborigin/KURL.h"
 #include "public/platform/WebScheduler.h"
 #include "public/platform/WebThread.h"
 #include "wtf/Functional.h"
 #include "wtf/Noncopyable.h"
-#include "wtf/WeakPtr.h"
 #include "wtf/text/WTFString.h"
 #include <limits.h>
 
 namespace blink {
 
 class WorkerMicrotaskRunner : public WebThread::TaskObserver {
 public:
     explicit WorkerMicrotaskRunner(WorkerThread* workerThread)
         : m_workerThread(workerThread)
     {
@@ skipping 390 matching lines @@
     } while (task && m_pausedInDebugger);
     InspectorInstrumentation::didLeaveNestedRunLoop(m_workerGlobalScope.get());
 }
 
 void WorkerThread::stopRunningDebuggerTasksOnPause()
 {
     m_pausedInDebugger = false;
 }
 
 } // namespace blink