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

Source/platform/exported/WebMediaStreamSource.cpp

 /*
  * Copyright (C) 2011 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 160 matching lines @@
     return m_private->requiresAudioConsumer();
 }
 
 class ConsumerWrapper final : public AudioDestinationConsumer {
 public:
     static ConsumerWrapper* create(WebAudioDestinationConsumer* consumer)
     {
         return new ConsumerWrapper(consumer);
     }
 
-    virtual void setFormat(size_t numberOfChannels, float sampleRate) override;
-    virtual void consumeAudio(AudioBus*, size_t numberOfFrames) override;
+    void setFormat(size_t numberOfChannels, float sampleRate) override;
+    void consumeAudio(AudioBus*, size_t numberOfFrames) override;
 
     WebAudioDestinationConsumer* consumer() { return m_consumer; }
 
 private:
     explicit ConsumerWrapper(WebAudioDestinationConsumer* consumer) : m_consumer(consumer) { }
 
     // m_consumer is not owned by this class.
     WebAudioDestinationConsumer* m_consumer;
 };
 
@@ skipping 34 matching lines @@
         ConsumerWrapper* wrapper = static_cast<ConsumerWrapper*>(it->get());
         if (wrapper->consumer() == consumer) {
             m_private->removeAudioConsumer(wrapper);
             return true;
         }
     }
     return false;
 }
 
 } // namespace blink