Update modules classes to use OVERRIDE / FINAL when needed

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 a15b6fa5122fd2b243adf3c4f59eebba9d8fdfd5..eda74a6ad59e61683efaf071b5371198b6b4dd07 100644
--- a/Source/modules/webaudio/ChannelMergerNode.h
+++ b/Source/modules/webaudio/ChannelMergerNode.h
@@ -36,16 +36,16 @@ namespace WebCore {
 
 class AudioContext;
 
-class ChannelMergerNode : public AudioNode {
+class ChannelMergerNode FINAL : public AudioNode {
 public:
     static PassRefPtr<ChannelMergerNode> create(AudioContext*, float sampleRate, unsigned numberOfInputs);
 
     // AudioNode
-    virtual void process(size_t framesToProcess);
-    virtual void reset();
+    virtual void process(size_t framesToProcess) OVERRIDE;
+    virtual void reset() OVERRIDE;
 
     // Called in the audio thread (pre-rendering task) when the number of channels for an input may have changed.
-    virtual void checkNumberOfChannelsForInput(AudioNodeInput*);
+    virtual void checkNumberOfChannelsForInput(AudioNodeInput*) OVERRIDE;
 
 private:
     unsigned m_desiredNumberOfOutputChannels;