Allow one undrawn frame in ShouldSendBeginFrame

If the renderer ever takes longer than the display deadline to submit
a frame, the previous logic would cause us to throttle one renderer
frame, leading to additional jank.

While this does allow for some "catch-up", we've seen cases where
this throttling can happen multiple times in a short period (<1s). In
these cases the throttling just adds additional jank.

Bug: 935630
Change-Id: I7c2c6d562ee91fbae316185e9e54385a1eebfc08
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1521967
Commit-Queue: Eric Karl <ericrk@chromium.org>
Reviewed-by: Saman Sami <samans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#642186}
5 files changed