The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8b43b3575a143939899fad7c4d9232c8e0a965ca

commit 8b43b3575a143939899fad7c4d9232c8e0a965ca
Author: David Reveman <reveman@chromium.org>
Date: Fri Nov 03 15:24:51 2017

exo: Implement async sub-surface support

This implements basic support for async sub-surface mode. It can
be improved by splitting parent and child into different
compositor frames but that's not needed for correct behavior.

Bug:  740110 
Test: exo_unittest --gtest_filter=SubSurfaceTest.SetCommitBehavior
Change-Id: Iaf18fc76486944ee07aa3e9004e79ea65753f861
Reviewed-on: https://chromium-review.googlesource.com/752362
Reviewed-by: Peng Huang <penghuang@chromium.org>
Commit-Queue: David Reveman <reveman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#513786}
[modify] https://crrev.com/8b43b3575a143939899fad7c4d9232c8e0a965ca/components/exo/sub_surface.cc
[modify] https://crrev.com/8b43b3575a143939899fad7c4d9232c8e0a965ca/components/exo/sub_surface_unittest.cc
[modify] https://crrev.com/8b43b3575a143939899fad7c4d9232c8e0a965ca/components/exo/surface.cc
[modify] https://crrev.com/8b43b3575a143939899fad7c4d9232c8e0a965ca/components/exo/surface.h
[modify] https://crrev.com/8b43b3575a143939899fad7c4d9232c8e0a965ca/components/exo/surface_tree_host.cc

Fixed. Please open another bug if we want to improve this using multiple frame sinks.