Implement media cast buttons

Source/core/html/shadow/MediaControlElements.h

Index: Source/core/html/shadow/MediaControlElements.h
diff --git a/Source/core/html/shadow/MediaControlElements.h b/Source/core/html/shadow/MediaControlElements.h
index 06c03206b756a4ca298aa6183bb0f85adf9263aa..3b2ab55306cccf110ccd8bd5fbcf7541f1e74d87 100644
--- a/Source/core/html/shadow/MediaControlElements.h
+++ b/Source/core/html/shadow/MediaControlElements.h
@@ -186,6 +186,23 @@ private:
 
 // ----------------------------
 
+class MediaControlCastOffButtonElement FINAL : public MediaControlInputElement {
+public:
+    static PassRefPtrWillBeRawPtr<MediaControlCastOffButtonElement> create(MediaControls&);
+
+    virtual bool willRespondToMouseClickEvents() OVERRIDE { return true; }
+
+    void setIsCasting(bool);
+
+private:
+    explicit MediaControlCastOffButtonElement(MediaControls&);
+
+    virtual const AtomicString& shadowPseudoId() const OVERRIDE;
+    virtual void defaultEventHandler(Event*) OVERRIDE;
+};
+
+// ----------------------------
+
 class MediaControlVolumeSliderElement FINAL : public MediaControlInputElement {
 public:
     static PassRefPtrWillBeRawPtr<MediaControlVolumeSliderElement> create(MediaControls&);