[webkit-reviews] review requested: [Bug 137438] Use is<>() / downcast<>() for TextTrack subclasses : [Attachment 239308] Patch

[bugzilla-daemon at webkit.org]

Chris Dumez <cdumez at apple.com> has asked  for review:
Bug 137438: Use is<>() / downcast<>() for TextTrack subclasses
https://bugs.webkit.org/show_bug.cgi?id=137438

Attachment 239308: Patch
https://bugs.webkit.org/attachment.cgi?id=239308&action=review