Fix synchronization bug in video to webgl texture upload

TexImage2D calls with a video element as a source were sometimes
failing because of a texture copy that was missing posterior
synchronization. This meant that it was possible for the source
texture to be recycled by skia (in a different command stream)
before the copy is executed.

BUG=807974
TBR=xlai@chromium.org

Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: I5f5124e45e803240507a676e75b2183cf564e1ab
Reviewed-on: https://chromium-review.googlesource.com/945331
Reviewed-by: Justin Novosad <junov@chromium.org>
Cr-Commit-Position: refs/branch-heads/3325@{#644}
Cr-Branched-From: bc084a8b5afa3744a74927344e304c02ae54189f-refs/heads/master@{#530369}
1 file changed