Updated from http://khronos.org/registry/OpenGL/api/GLES2/gl2ext.h

BUG=chromium:849576

Change-Id: I80e07fad80899b96b037a978855b70ff25bb5bd9
Reviewed-on: https://chromium-review.googlesource.com/1107494
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>