GitLab

Ensure that we use upload tasks for uploading bitmaps in the Gpu image
cache. This allows the image to be locked across multiple tasks.

R=ericrk@chromium.org

Bug: 791828
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I7f82f2001846df02469e9976d12581706c1673b7
Reviewed-on: https://chromium-review.googlesource.com/1041525
Commit-Queue: Khushal <khushalsagar@chromium.org>
Reviewed-by: Eric Karl <ericrk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555849}