[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: https://svn.webkit.org/repository/webkit/trunk/Source/Platform/chromium/public@140158 268f45cc-cd09-0410-ab3c-d52691b4dbfc