Deflake WebMediaPlayerMSTest.RotationChange

This test currently relies upon the exact ordering of RenderFrame,
InjectFrame and CheckForFrameChanges, which is a mix of delayed and
immediate tasks. The scheduler doesn't guarantee the exact ordering
of these which causes this test to flake.  We add some extra
RunLoop().RunUntilIdle() calls to ensure CheckForFrameChanges has
a chance to run.

TBR=miu@chromium.org

Bug: 863341, 891670
Change-Id: I526d6b77f6ce46f04d84584f5daba096ef1a98e5
Reviewed-on: https://chromium-review.googlesource.com/c/1365248
Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Reviewed-by: Alex Clarke <alexclarke@chromium.org>
Commit-Queue: Alex Clarke <alexclarke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#614351}
1 file changed