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

Source/modules/webaudio/ChannelMergerNode.h

Index: Source/modules/webaudio/ChannelMergerNode.h
diff --git a/Source/modules/webaudio/ChannelMergerNode.h b/Source/modules/webaudio/ChannelMergerNode.h
index e17da1f4dcf587cad4828c3ada8b6eb5e2135779..e4374f1cead755956eafab25a709a0e0e3a82909 100644
--- a/Source/modules/webaudio/ChannelMergerNode.h
+++ b/Source/modules/webaudio/ChannelMergerNode.h
@@ -40,9 +40,9 @@ class ChannelMergerHandler final : public AudioHandler {
 public:
     static PassRefPtr<ChannelMergerHandler> create(AudioNode&, float sampleRate, unsigned numberOfInputs);
 
-    virtual void process(size_t framesToProcess) override;
-    virtual void setChannelCount(unsigned long, ExceptionState&) final;
-    virtual void setChannelCountMode(const String&, ExceptionState&) final;
+    void process(size_t framesToProcess) override;
+    void setChannelCount(unsigned long, ExceptionState&) final;
+    void setChannelCountMode(const String&, ExceptionState&) final;
 
 private:
     ChannelMergerHandler(AudioNode&, float sampleRate, unsigned numberOfInputs);