[DL]: Fix yielding budget to ensure it marks the next phase.

This patch updates the layout dirty bit propagation to mark the container
itself when children have changed.

It also ensures that the yielding budget marks the next phase for
propagation, even if it isn't sure whether we need to do that phase.

This is needed so that we don't accidentally skip a phase.

R=chrishtr@chromium.org

Bug: 882663
Change-Id: Icebe1d3960639bee88d18acc7dd2618394053552
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1531014
Commit-Queue: vmpstr <vmpstr@chromium.org>
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#642627}
7 files changed