Support text track selection in video controls

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 5f72cd0edd2f38c690290c07e01546869d60e726..1f55abad5d85192d1eba56b8a5b0452cbb53eb5e 100644
--- a/Source/core/html/shadow/MediaControlElements.h
+++ b/Source/core/html/shadow/MediaControlElements.h
@@ -34,6 +34,8 @@
 
 namespace blink {
 
+class TextTrack;
+
 // ----------------------------
 
 class MediaControlPanelElement final : public MediaControlDivElement {
@@ -146,6 +148,28 @@ private:
 
 // ----------------------------
 
+class MediaControlTextTrackListElement final : public MediaControlDivElement {
+public:
+    static PassRefPtrWillBeRawPtr<MediaControlTextTrackListElement> create(MediaControls&);
+
+    virtual bool willRespondToMouseClickEvents() override { return true; }
+
+    void refreshTextTrackListMenu();
+
+private:
+    explicit MediaControlTextTrackListElement(MediaControls&);
+
+    virtual void defaultEventHandler(Event*) override;
+
+    String getTextTrackLabel(TextTrack*);
+
+    RefPtrWillBeRawPtr<Element> createTextTrackListItem(TextTrack*);
+
+    void showTextTrackAtIndex(unsigned);
+};
+
+// ----------------------------
+
 class MediaControlTimelineElement final : public MediaControlInputElement {
 public:
     static PassRefPtrWillBeRawPtr<MediaControlTimelineElement> create(MediaControls&);