Separate the text track container from the media controls

Source/core/html/shadow/MediaControls.h

Index: Source/core/html/shadow/MediaControls.h
diff --git a/Source/core/html/shadow/MediaControls.h b/Source/core/html/shadow/MediaControls.h
index db9593b0b24afa51360b933ba8f6b96fc0e0a246..889e5ab63e67f6bcb7f079ba94c29d82bbe519b7 100644
--- a/Source/core/html/shadow/MediaControls.h
+++ b/Source/core/html/shadow/MediaControls.h
@@ -68,8 +68,6 @@ public:
     void refreshCastButtonVisibility();
     void showOverlayCastButton();
 
-    TextTrackContainer* textTrackContainer();
-
     void mediaElementFocused();
 
     DECLARE_VIRTUAL_TRACE();
@@ -112,9 +110,6 @@ private:
     // Container for the media control elements.
     RawPtrWillBeMember<MediaControlPanelElement> m_panel;
 
-    // Container for the text track cues.
-    RawPtrWillBeMember<TextTrackContainer> m_textTrackContainer;
-
     // Media control elements.
     RawPtrWillBeMember<MediaControlOverlayPlayButtonElement> m_overlayPlayButton;
     RawPtrWillBeMember<MediaControlOverlayEnclosureElement> m_overlayEnclosure;