Renames the macro to be more ANGLE-ey.

Refactoring only.

Bug: angleproject:1671
Change-Id: I8f2dd227c7e2025886ec66e85efa877ea261d0ad
Reviewed-on: https://chromium-review.googlesource.com/1036209Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>