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

Source/web/WebLeakDetector.cpp

 /*
  * 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 49 matching lines @@
 public:
     explicit WebLeakDetectorImpl(WebLeakDetectorClient* client)
         : m_client(client)
         , m_delayedGCAndReportTimer(this, &WebLeakDetectorImpl::delayedGCAndReport)
         , m_delayedReportTimer(this, &WebLeakDetectorImpl::delayedReport)
         , m_numberOfGCNeeded(0)
     {
         ASSERT(m_client);
     }
 
-    virtual ~WebLeakDetectorImpl() { }
+    ~WebLeakDetectorImpl() override {}
 
-    virtual void collectGarbageAndGetDOMCounts(WebLocalFrame*) override;
+    void collectGarbageAndGetDOMCounts(WebLocalFrame*) override;
 
 private:
     void delayedGCAndReport(Timer<WebLeakDetectorImpl>*);
     void delayedReport(Timer<WebLeakDetectorImpl>*);
 
     WebLeakDetectorClient* m_client;
     Timer<WebLeakDetectorImpl> m_delayedGCAndReportTimer;
     Timer<WebLeakDetectorImpl> m_delayedReportTimer;
     int m_numberOfGCNeeded;
 };
@@ skipping 63 matching lines @@
 }
 
 } // namespace
 
 WebLeakDetector* WebLeakDetector::create(WebLeakDetectorClient* client)
 {
     return new WebLeakDetectorImpl(client);
 }
 
 } // namespace blink