Remove the DataFormat that was only used in CG port in GraphicsContext3D
Remove the DataFormat that was only used in CG port in GraphicsContext3D

BUG=237774

Review URL: https://chromiumcodereview.appspot.com/14915002

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@149770 bbb929c8-8fbe-4397-9dbb-9b2b20218538

primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs