Fix virtual/override/final usage in Source/platform/.

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 137 matching lines @@
 class Timer : public TimerBase {
 public:
     typedef void (TimerFiredClass::*TimerFiredFunction)(Timer*);
 
     Timer(TimerFiredClass* o, TimerFiredFunction f)
         : m_object(o), m_function(f)
     {
     }
 
 protected:
-    virtual void fired() override
+    void fired() override
     {
         (m_object->*m_function)(this);
     }
 
     NO_LAZY_SWEEP_SANITIZE_ADDRESS
-    virtual bool canFire() const override
+    bool canFire() const override
     {
         // Oilpan: if a timer fires while Oilpan heaps are being lazily
         // swept, it is not safe to proceed if the object is about to
         // be swept (and this timer will be stopped while doing so.)
         return TimerIsObjectAliveTrait<TimerFiredClass>::isHeapObjectAlive(m_object);
     }
 
 private:
     // FIXME: Oilpan: TimerBase should be moved to the heap and m_object should be traced.
     // This raw pointer is safe as long as Timer<X> is held by the X itself (That's the case
     // in the current code base).
     GC_PLUGIN_IGNORE("363031")
     TimerFiredClass* m_object;
     TimerFiredFunction m_function;
 };
 
 NO_LAZY_SWEEP_SANITIZE_ADDRESS
 inline bool TimerBase::isActive() const
 {
     ASSERT(m_thread == currentThread());
     return m_cancellableTimerTask;
 }
 
 } // namespace blink
 
 #endif // Timer_h