Remove initialized tracking code in WebGL classes

No longer needed as we always initialize vram in command buffer in gpu process

This is my per cleanup CL per week.

BUG=
TEST=tree
R=bajones@chromium.org,kbr@chromium.org

Review URL: https://codereview.chromium.org/158033002

git-svn-id: svn://svn.chromium.org/blink/trunk@166748 bbb929c8-8fbe-4397-9dbb-9b2b20218538