Make WebTaskRunner ThreadSafeRefCounted

third_party/WebKit/Source/platform/heap/GCTaskRunner.h

 /*
  * Copyright (C) 2014 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 25 matching lines @@
 #include "platform/heap/ThreadState.h"
 #include "public/platform/WebThread.h"
 #include "public/platform/WebTraceLocation.h"
 #include "wtf/PtrUtil.h"
 #include <memory>
 
 namespace blink {
 
 class MessageLoopInterruptor final : public BlinkGCInterruptor {
  public:
-  explicit MessageLoopInterruptor(WebTaskRunner* taskRunner)
-      : m_taskRunner(taskRunner) {}
+  explicit MessageLoopInterruptor(RefPtr<WebTaskRunner> taskRunner)
+      : m_taskRunner(std::move(taskRunner)) {}
 
   void requestInterrupt() override {
     // GCTask has an empty run() method. Its only purpose is to guarantee
     // that MessageLoop will have a task to process which will result
     // in GCTaskRunner::didProcessTask being executed.
     m_taskRunner->postTask(BLINK_FROM_HERE, crossThreadBind(&runGCTask));
   }
 
  private:
   static void runGCTask() {
     // Don't do anything here because we don't know if this is
     // a nested event loop or not. GCTaskRunner::didProcessTask
     // will enter correct safepoint for us.
     // We are not calling onInterrupted() because that always
     // conservatively enters safepoint with pointers on stack.
   }
 
-  WebTaskRunner* m_taskRunner;
+  RefPtr<WebTaskRunner> m_taskRunner;
 };
 
 class GCTaskObserver final : public WebThread::TaskObserver {
   USING_FAST_MALLOC(GCTaskObserver);
 
  public:
   GCTaskObserver() : m_nesting(0) {}
 
   ~GCTaskObserver() {
     // m_nesting can be 1 if this was unregistered in a task and
@@ skipping 34 matching lines @@
   ~GCTaskRunner() { m_thread->removeTaskObserver(m_gcTaskObserver.get()); }
 
  private:
   std::unique_ptr<GCTaskObserver> m_gcTaskObserver;
   WebThread* m_thread;
 };
 
 }  // namespace blink
 
 #endif