Ideas for text track container follow-up

Source/core/html/HTMLMediaElement.cpp

Index: Source/core/html/HTMLMediaElement.cpp
diff --git a/Source/core/html/HTMLMediaElement.cpp b/Source/core/html/HTMLMediaElement.cpp
index 01fb155c9d54554aa30e5000abcf3c0502ced348..9da9e343561663a2b3ecd14d0ee362b57e559417 100644
--- a/Source/core/html/HTMLMediaElement.cpp
+++ b/Source/core/html/HTMLMediaElement.cpp
@@ -45,6 +45,7 @@
 #include "core/html/HTMLMediaSource.h"
 #include "core/html/HTMLSourceElement.h"
 #include "core/html/HTMLTrackElement.h"
+#include "core/html/HTMLVideoElement.h"
 #include "core/html/MediaController.h"
 #include "core/html/MediaError.h"
 #include "core/html/MediaFragmentURIParser.h"
@@ -3228,7 +3229,9 @@ void HTMLMediaElement::updateTextTrackDisplay()
 {
     WTF_LOG(Media, "HTMLMediaElement::updateTextTrackDisplay(%p)", this);
 
-    ensureTextTrackContainer().updateDisplay(*this);
+    // not really, maybe move some things to HTMLVideoElement instead.
+    ASSERT(isHTMLVideoElement());
+    ensureTextTrackContainer().updateDisplay(toHTMLVideoElement(*this));
 }
 
 void HTMLMediaElement::setClosedCaptionsVisible(bool closedCaptionVisible)