GitLab

Make sure to invalidate the fence if context was lost, so that it
doesn't attempt to make gl calls during tear down.

BUG=777594

Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
Change-Id: I0722193e020fe01483d55e17d640a99061cdb7ea
Reviewed-on: https://chromium-review.googlesource.com/747381
Commit-Queue: Sadrul Chowdhury <sadrul@chromium.org>
Reviewed-by: Antoine Labour <piman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#512929}