Improve CancellableTaskFactory handling and Oilpan usage.

Source/platform/scheduler/CancellableTaskFactory.cpp

 // 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 "config.h"
 #include "platform/scheduler/CancellableTaskFactory.h"
 
 #include "public/platform/Platform.h"
 #include "wtf/InstanceCounter.h"
 
 namespace blink {
 
 void CancellableTaskFactory::cancel()
 {
     m_weakPtrFactory.revokeAll();
 }
 
 WebTaskRunner::Task* CancellableTaskFactory::cancelAndCreate()
 {
     cancel();
     return new CancellableTask(m_weakPtrFactory.createWeakPtr());
 }
 
-NO_LAZY_SWEEP_SANITIZE_ADDRESS
 void CancellableTaskFactory::CancellableTask::run()
 {
     if (CancellableTaskFactory* taskFactory = m_weakPtr.get()) {
-#if defined(ADDRESS_SANITIZER)
-        if (taskFactory->m_unpoisonBeforeUpdate)
-            ASAN_UNPOISON_MEMORY_REGION(reinterpret_cast<unsigned char*>(taskFactory), sizeof(CancellableTaskFactory));
-#endif
         Closure* closure = taskFactory->m_closure.get();
         taskFactory->m_weakPtrFactory.revokeAll();
         (*closure)();
     }
 }
 
 } // namespace blink