Revert "Implement GL_KHR_debug." This reverts commit 6c521b7a70a53b1c9f7762e53e34b5a8146b0f7b. Change-Id: I6ff981198e31f34d3e405edea6277ee75516d6ee Reviewed-on: https://chromium-review.googlesource.com/319820 Reviewed-by: Geoff Lang <geofflang@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>