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

Source/modules/webaudio/GainNode.h

Index: Source/modules/webaudio/GainNode.h
diff --git a/Source/modules/webaudio/GainNode.h b/Source/modules/webaudio/GainNode.h
index 8794a3f94d85f8f672ddfd8cf03c22936d8faff3..923ae57213ae546a9a2a22a010c85121e8d7e2cc 100644
--- a/Source/modules/webaudio/GainNode.h
+++ b/Source/modules/webaudio/GainNode.h
@@ -42,10 +42,10 @@ public:
     static PassRefPtr<GainHandler> create(AudioNode&, float sampleRate, AudioParamHandler& gain);
 
     // AudioHandler
-    virtual void process(size_t framesToProcess) override;
+    void process(size_t framesToProcess) override;
 
     // Called in the main thread when the number of channels for the input may have changed.
-    virtual void checkNumberOfChannelsForInput(AudioNodeInput*) override;
+    void checkNumberOfChannelsForInput(AudioNodeInput*) override;
 
 private:
     GainHandler(AudioNode&, float sampleRate, AudioParamHandler& gain);