The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a15e976b52b92c65ad791be142dbd5f11364ae07

commit a15e976b52b92c65ad791be142dbd5f11364ae07
Author: gklassen <gklassen@chromium.org>
Date: Thu Jun 15 22:22:54 2017

Add SurfaceWillDraw notification

Adds a SurfaceWillDraw notification to allow observers to monitor as
surfaces are added to the next display frame.

Viz will implement a hit-test component that will aggregate hit-test
information published along with compositor frames.  The aggregated
data will be made available for hit testing in a shared memory object.

In order to ensure that the hit-test information matches the current
information for the frame it needs to know which surfaces have been
added to the current DisplayFrame.

A method has been added to Surface observer so that observers will be
notified as surfaces are added to the Display frame.  The notification
is invoked during Surface Aggregation at the same place and following
the same convention as the existing RunWillDrawCallback - the key
difference being that this implementation allows one observer to
monitor all surfaces without creating observers for each surface
instance.

BUG=732398
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Review-Url: https://codereview.chromium.org/2938833002
Cr-Commit-Position: refs/heads/master@{#479865}

[modify] https://crrev.com/a15e976b52b92c65ad791be142dbd5f11364ae07/cc/surfaces/display_scheduler.cc
[modify] https://crrev.com/a15e976b52b92c65ad791be142dbd5f11364ae07/cc/surfaces/display_scheduler.h
[modify] https://crrev.com/a15e976b52b92c65ad791be142dbd5f11364ae07/cc/surfaces/surface_aggregator.cc
[modify] https://crrev.com/a15e976b52b92c65ad791be142dbd5f11364ae07/cc/surfaces/surface_aggregator_unittest.cc
[modify] https://crrev.com/a15e976b52b92c65ad791be142dbd5f11364ae07/cc/surfaces/surface_manager.cc
[modify] https://crrev.com/a15e976b52b92c65ad791be142dbd5f11364ae07/cc/surfaces/surface_manager.h
[modify] https://crrev.com/a15e976b52b92c65ad791be142dbd5f11364ae07/cc/surfaces/surface_observer.h
[modify] https://crrev.com/a15e976b52b92c65ad791be142dbd5f11364ae07/cc/test/fake_surface_observer.cc
[modify] https://crrev.com/a15e976b52b92c65ad791be142dbd5f11364ae07/cc/test/fake_surface_observer.h
[modify] https://crrev.com/a15e976b52b92c65ad791be142dbd5f11364ae07/components/viz/service/frame_sinks/mojo_frame_sink_manager.cc
[modify] https://crrev.com/a15e976b52b92c65ad791be142dbd5f11364ae07/components/viz/service/frame_sinks/mojo_frame_sink_manager.h

Cleaning up old Proj-Mustash labels.