Adding RB label as this is a recent regression

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/7ea3a9cd847d7478598d22804d04c32c156c14f4

commit 7ea3a9cd847d7478598d22804d04c32c156c14f4
Author: enne <enne@chromium.org>
Date: Mon Jun 27 21:38:43 2016

Revert of Turn on enable begin frame scheduling by default (patchset #11 id:200001 of https://codereview.chromium.org/1939253002/ )

Reason for revert:
Causes smoothness regressions, other bugs

BUG= 623174 , 623467 , 623490 

Original issue's description:
> Turn on enable begin frame scheduling by default
>
> This turns on --enable-begin-frame-scheduling[1] for all[2] platforms.
> This was already on for Android so should only be a real change
> for desktop / ChromeOS platforms.
>
> Lots of cleanup can follow from this like removing all commit vsync /
> authoritative vsync / CompositorVSyncManager things, but this is a
> smaller patch to suss out any performance regressions.
>
> [1] In this case, "begin frame scheduling" means browser->renderer
> begin frame ticks instead of sending vsync information and having
> a synthetic source on the renderer side.
>
> [2] MUS is not hooked up to begin frame scheduling yet, but
> mojo:mash_session in an "oxygen" build still works with this patch
> applied.  Blimp also doesn't use begin frame scheduling and will
> eventually just be transitioned to a synthetic begin frame source
> for its engine half.
>
> CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel
>
> Committed: https://crrev.com/f2d7f5e1891703ec4384ededd80f896816921204
> Cr-Commit-Position: refs/heads/master@{#401796}

TBR=boliu@chromium.org,piman@chromium.org,skyostil@chromium.org,sunnyps@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.

Review-Url: https://codereview.chromium.org/2100203002
Cr-Commit-Position: refs/heads/master@{#402294}

[modify] https://crrev.com/7ea3a9cd847d7478598d22804d04c32c156c14f4/android_webview/lib/main/aw_main_delegate.cc
[modify] https://crrev.com/7ea3a9cd847d7478598d22804d04c32c156c14f4/cc/base/switches.cc
[modify] https://crrev.com/7ea3a9cd847d7478598d22804d04c32c156c14f4/cc/base/switches.h
[modify] https://crrev.com/7ea3a9cd847d7478598d22804d04c32c156c14f4/chrome/browser/chromeos/login/chrome_restart_request.cc
[modify] https://crrev.com/7ea3a9cd847d7478598d22804d04c32c156c14f4/content/browser/android/content_startup_flags.cc
[modify] https://crrev.com/7ea3a9cd847d7478598d22804d04c32c156c14f4/content/browser/compositor/browser_compositor_output_surface.cc
[modify] https://crrev.com/7ea3a9cd847d7478598d22804d04c32c156c14f4/content/browser/renderer_host/render_process_host_impl.cc
[modify] https://crrev.com/7ea3a9cd847d7478598d22804d04c32c156c14f4/content/renderer/gpu/render_widget_compositor.cc
[modify] https://crrev.com/7ea3a9cd847d7478598d22804d04c32c156c14f4/ui/compositor/compositor.cc

Tested this issue on Mac OS 10.11.5 using chrome latest canary M53-53.0.2784.0 by following steps mentioned in the original comment. Observed the print preview page is stopped as expected after ending the process from task manager. Since the issue is working as intended adding TE-Verified label.

Thanks!

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enne@: Please let us know if there is further work to be done on this. If not please update the status of the bug as the revert is verified in C#3.