Revert "Enable needed extensions in generated GLSL shaders and call them when possible." This reverts commit 233b334213c1a4853e81f71ba90aa223b2a68dce. Change-Id: Id99024b736324ad030ce63c5d0baae32b6d7f54b Reviewed-on: https://chromium-review.googlesource.com/311181 Reviewed-by: Geoff Lang <geofflang@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>