[jumbo] Merged two GetActiveTextureUnit functions

In jumbo build experiments, two (identical but small)
GetActiveTextureUnit() functions ended up in the same translation
unit which caused the compiler to fail.

This patch moves the useful function into a shared utility file.

Bug: 801580
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel
Change-Id: Id6f8f1002db18593150bec30f1e8b7092f464e13
Reviewed-on: https://chromium-review.googlesource.com/1136308
Reviewed-by: danakj <danakj@chromium.org>
Commit-Queue: Daniel Bratell <bratell@opera.com>
Cr-Commit-Position: refs/heads/master@{#575721}
1 file changed