Changed all GC3D types to their standard GL counterparts

This is a second attempt of https://codereview.chromium.org/99133014/, now that
the Khronos headers have been updated to account for the 64-bit issues from last
time

BUG=326382
TBR=adamk@chromium.org

Review URL: https://codereview.chromium.org/122693002

git-svn-id: svn://svn.chromium.org/blink/trunk@164430 bbb929c8-8fbe-4397-9dbb-9b2b20218538