Revert "Updated GC3D typedefs to use their standard GL counterparts."

This reverts http://src.chromium.org/viewvc/blink?revision=163820&view=revision

It doesn't build on Win64 due to a bad definition of khronos_intptr_t
in third_party/khronos/KHR/khrplatform.h (Win64 is LLP64).

BUG=326382
TBR=bajones@chromium.org,kbr@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/114263004

git-svn-id: svn://svn.chromium.org/blink/trunk@163831 bbb929c8-8fbe-4397-9dbb-9b2b20218538