Update modules classes to use OVERRIDE / FINAL when needed

Source/modules/mediastream/MediaStream.h

Index: Source/modules/mediastream/MediaStream.h
diff --git a/Source/modules/mediastream/MediaStream.h b/Source/modules/mediastream/MediaStream.h
index 867eda65f28f9b47b79dc6b3827744f6a18fb793..e2dfd8bbf0842a885b4b71c9ddf1f2bcb81d00b4 100644
--- a/Source/modules/mediastream/MediaStream.h
+++ b/Source/modules/mediastream/MediaStream.h
@@ -40,7 +40,7 @@ namespace WebCore {
 
 class ExceptionState;
 
-class MediaStream : public RefCounted<MediaStream>, public ScriptWrappable, public URLRegistrable, public MediaStreamDescriptorClient, public EventTargetWithInlineData, public ContextLifecycleObserver {
+class MediaStream FINAL : public RefCounted<MediaStream>, public ScriptWrappable, public URLRegistrable, public MediaStreamDescriptorClient, public EventTargetWithInlineData, public ContextLifecycleObserver {
     REFCOUNTED_EVENT_TARGET(MediaStream);
 public:
     static PassRefPtr<MediaStream> create(ExecutionContext*);
@@ -85,7 +85,7 @@ protected:
     MediaStream(ExecutionContext*, PassRefPtr<MediaStreamDescriptor>);
 
     // ContextLifecycleObserver
-    virtual void contextDestroyed();
+    virtual void contextDestroyed() OVERRIDE;
 
 private:
     // MediaStreamDescriptorClient