Clean up MediaControlElement virtual and unused functions

Source/core/html/shadow/MediaControlElementTypes.h

Index: Source/core/html/shadow/MediaControlElementTypes.h
diff --git a/Source/core/html/shadow/MediaControlElementTypes.h b/Source/core/html/shadow/MediaControlElementTypes.h
index c998baa9e7e2864b56a3042fee182aab34a3d4f4..e80ee79bc3794e4c05919ff6aa37af799de54489 100644
--- a/Source/core/html/shadow/MediaControlElementTypes.h
+++ b/Source/core/html/shadow/MediaControlElementTypes.h
@@ -73,21 +73,19 @@ MediaControlElementType mediaControlElementType(Node*);
 
 class MediaControlElement {
 public:
-    virtual void hide();
-    virtual void show();
-    virtual bool isShowing() const;
+    void hide();
+    void show();
 
-    virtual MediaControlElementType displayType() { return m_displayType; }
-    virtual const AtomicString& shadowPseudoId() const = 0;
+    MediaControlElementType displayType() { return m_displayType; }
 
-    virtual void setMediaController(MediaControllerInterface* controller) { m_mediaController = controller; }
+    void setMediaController(MediaControllerInterface* controller) { m_mediaController = controller; }
     MediaControllerInterface* mediaController() const { return m_mediaController; }
 
 protected:
     explicit MediaControlElement(MediaControlElementType, HTMLElement*);
     ~MediaControlElement() { }
 
-    virtual void setDisplayType(MediaControlElementType);
+    void setDisplayType(MediaControlElementType);
 
 private:
     MediaControllerInterface* m_mediaController;