VideoSurfaceLayer: add flag to force frame submission regardless of visibility.

Picture-in-Picture requires submission even if the video may appear as
not visible to the frame submitter. This is adding a flag that is turned
on when a video enters Picture-in-Picture.

Bug: 865940
Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_slimming_paint_v2;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I98ece11c4ad91ba2c34cafad711c50068fc91384
Reviewed-on: https://chromium-review.googlesource.com/1147542
Commit-Queue: Mounir Lamouri <mlamouri@chromium.org>
Reviewed-by: Frank Liberato <liberato@chromium.org>
Reviewed-by: CJ DiMeglio <lethalantidote@chromium.org>
Reviewed-by: Philip Rogers <pdr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577781}
11 files changed