[chromium] Remove the contents of WebVideoFrame class
https://bugs.webkit.org/show_bug.cgi?id=106037

Reviewed by James Robinson.

This class becomes an empty base class now, used only for the API
boundary.

* chromium/public/WebVideoFrame.h:
(WebKit):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@144946 268f45cc-cd09-0410-ab3c-d52691b4dbfc