Revert 174516 "Oilpan: Use transition types for HTMLCanvasElement."

Broke Android build. See
https://code.google.com/p/chromium/issues/detail?id=357163#c65 .

> Oilpan: Use transition types for HTMLCanvasElement.
> 
> BUG=357163
> R=haraken@chromium.org
> 
> Review URL: https://codereview.chromium.org/292113004

TBR=zerny@chromium.org

Review URL: https://codereview.chromium.org/292203006

git-svn-id: svn://svn.chromium.org/blink/trunk@174520 bbb929c8-8fbe-4397-9dbb-9b2b20218538