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This reverts commit 1374013c and
disables some media tests that flake due to a race that is exposed
by the revert.

Reason for revert: causes jank https://crbug.com/947587
The original reason for landing this CL does not apply anymore. It is
no longer the case that viz skips a BeginFrame if an undrawn frame
exists. See https://crrev.com/c/1521967

Original change's description:
> Skip MISSED frames in browser compositor
>
> This CL fixes a dropped frame issue when a scroll transitions from
> dragging to a momentum "fling" phase. When the user is scrolling and
> lifts their finger with velocity, the scroll continues according to a
> decelerating animation curve. When this happens, the FlingController
> receives a FlingStart instead of a ScrollUpdate and it uses that to
> create an animation curve.
>
> When this happens the browser process registers itself as an animation
> observer so that it begins to receive BeginFrame signals. However, the
> display service issues a MISSED BeginFrame for the frame in which the
> animation was registered. This will frequently miss submission in the
> current frame, so it submit next frame and won't receive a BeginFrame
> then. This leads to a frame without the browser ticking the fling
> animation. See https://crbug.com/882907#c50 for a diagram and more
> complete explanation of the issue.
>
> The browser process shouldn't require processing MISSED frames so in
> this CL we simply drop MISSED frames if we're in the browser compositor
> (commit_to_active_tree is true). Longer term, the display scheduler
> should make these decisions but this is an immediate fix for the fling
> issue.
>
> Bug: 882907
> Change-Id: Ieb6d14051dc05c5e177da1920dbd27684f941d29
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1517164
> Commit-Queue: David Bokan <bokan@chromium.org>
> Reviewed-by: Sunny Sachanandani <sunnyps@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#640172}

TBR=bokan@chromium.org,sunnyps@chromium.org


Bug: 947587,882907,963141
Change-Id: Id23b586f89de67f9e77212ee265f4ad2db5a6fe7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1613363Reviewed-by: Saman Sami <samans@chromium.org>
Reviewed-by: David Bokan <bokan@chromium.org>
Commit-Queue: Saman Sami <samans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#660014}