Deduplicated a gpu code helper function to avoid jumbo clashes

There are three identical small ToGLuint functions which clashed
in jumbo build experiments. This moves it to gles2_cmd_utils.h and
changes the type to not add a dependency on GL in
command_buffer/common.

Bug: 864986
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: Iad7cfc8a2506b765ba7a93c2eb9dc59149e5b8f4
Reviewed-on: https://chromium-review.googlesource.com/1141944
Reviewed-by: Antoine Labour <piman@chromium.org>
Commit-Queue: Daniel Bratell <bratell@opera.com>
Cr-Commit-Position: refs/heads/master@{#577499}
4 files changed