Make blink::TimerBase own the WebTaskRunner for timer task

third_party/WebKit/Source/platform/Timer.h

 /*
  * Copyright (C) 2006 Apple Computer, 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 112 matching lines @@
         }
 
     private:
         TimerBase* m_timer; // NOT OWNED
     };
 
     double m_nextFireTime; // 0 if inactive
     double m_repeatInterval; // 0 if not repeating
     WebTraceLocation m_location;
     CancellableTimerTask* m_cancellableTimerTask; // NOT OWNED
-    WebTaskRunner* m_webTaskRunner; // Not owned.
+    std::unique_ptr<WebTaskRunner> m_webTaskRunner;
 
 #if DCHECK_IS_ON()
     ThreadIdentifier m_thread;
 #endif
 
     friend class ThreadTimers;
     friend class TimerHeapLessThanFunction;
     friend class TimerHeapReference;
 };
 
@@ skipping 82 matching lines @@
 NO_LAZY_SWEEP_SANITIZE_ADDRESS
 inline bool TimerBase::isActive() const
 {
     ASSERT(m_thread == currentThread());
     return m_cancellableTimerTask;
 }
 
 } // namespace blink
 
 #endif // Timer_h