Removing OSMesa specific workarounds

Now that SwiftShader has replaced OSMesa, we can remove all OSMesa
specific workarounds in chromium.

Bug: chromium:873321 chromium:174845 chromium:348350 chromium:347967

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: I12fe2de6f7ea963ca9ebeeee1f35cd54e4cbecd0
Reviewed-on: https://chromium-review.googlesource.com/1175450
Reviewed-by: Bruce Dawson <brucedawson@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Reviewed-by: enne <enne@chromium.org>
Reviewed-by: Michael Moss <mmoss@chromium.org>
Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Alexis H├ętu <sugoi@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#586326}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 3384f06d7fd5e0ebc07fabcf9f5b9a1d0996b927
1 file changed