Suspecting root cause by a270ee750d219073bf1d332a40eb67142a9b0f98

Reverting

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c02a3255e2f1821c6dd308177bf3e2679d546f5f

commit c02a3255e2f1821c6dd308177bf3e2679d546f5f
Author: Luna Lu <loonybear@chromium.org>
Date: Tue Nov 14 15:56:08 2017

Revert "Add aura::WindowOcclusionTracker."

This reverts commit a270ee750d219073bf1d332a40eb67142a9b0f98.

Reason for revert: <INSERT REASONING HERE>

Original change's description:
> Add aura::WindowOcclusionTracker.
> 
> aura::WindowOcclusionTracker notifies interested windows
> when their occlusion state change.
> 
> This will be used to release resources and throttle execution
> of occluded tabs.
> 
> Time to recompute occlusion on a Samsung Chromebook Pro:
>  100 partially occluded windows*: 108us
>  50 partially occluded windows*: 50us
> * window 0 at position (x=0;y=0), window 1 at position (x=1;y=1),
>   window 2 at position (x=2;y=2), etc.
> Benchmark code:
> https://chromium-review.googlesource.com/c/chromium/src/+/718979
> 
> 
> Bug: 738387
> Change-Id: I65e9e3eb58461e14eda280a133f0acb23a9f1c40
> Reviewed-on: https://chromium-review.googlesource.com/679206
> Commit-Queue: François Doray <fdoray@chromium.org>
> Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#516293}

TBR=sadrul@chromium.org,fdoray@chromium.org

Change-Id: Ib9d0056b520f8fef13d97f0736dbde197c14882d
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug:  784879 
Reviewed-on: https://chromium-review.googlesource.com/768168
Reviewed-by: Luna Lu <loonybear@chromium.org>
Commit-Queue: Luna Lu <loonybear@chromium.org>
Cr-Commit-Position: refs/heads/master@{#516311}
[modify] https://crrev.com/c02a3255e2f1821c6dd308177bf3e2679d546f5f/ui/aura/BUILD.gn
[modify] https://crrev.com/c02a3255e2f1821c6dd308177bf3e2679d546f5f/ui/aura/window.cc
[modify] https://crrev.com/c02a3255e2f1821c6dd308177bf3e2679d546f5f/ui/aura/window.h
[modify] https://crrev.com/c02a3255e2f1821c6dd308177bf3e2679d546f5f/ui/aura/window_delegate.h
[delete] https://crrev.com/6ffeca5e9aa6c4dc57bb4873b4bc2ec746dcf628/ui/aura/window_occlusion_tracker.cc
[delete] https://crrev.com/6ffeca5e9aa6c4dc57bb4873b4bc2ec746dcf628/ui/aura/window_occlusion_tracker.h
[delete] https://crrev.com/6ffeca5e9aa6c4dc57bb4873b4bc2ec746dcf628/ui/aura/window_occlusion_tracker_unittest.cc

Sorry about reverting your CL fdoray.

It seems like these tests have been flaky for a while. I am suspecting the same cause as Issue 774959.

grt@, could you please help take a look?

Thanks

I think this is the same issue as 774959, closing it as a dup.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/fe694a6581c8cc68065c305581506e0122c646ae

commit fe694a6581c8cc68065c305581506e0122c646ae
Author: Francois Doray <fdoray@chromium.org>
Date: Thu Nov 16 14:47:07 2017

Add aura::WindowOcclusionTracker [reland].

This Cl shouldn't have been reverted. See  https://crbug.com/784879#c5 

aura::WindowOcclusionTracker notifies interested windows
when their occlusion state change.

This will be used to release resources and throttle execution
of occluded tabs.

Time to recompute occlusion on a Samsung Chromebook Pro:
 100 partially occluded windows*: 108us
  50 partially occluded windows*: 50us
  * window 0 at position (x=0;y=0), window 1 at position (x=1;y=1),
    window 2 at position (x=2;y=2), etc.
    Benchmark code:
    https://chromium-review.googlesource.com/c/chromium/src/+/718979

TBR=sadrul@chromium.org

Bug: 738387,  784879 
Change-Id: Ie5a8559378223bb78693cd0cd40e4468889e9f79
Reviewed-on: https://chromium-review.googlesource.com/773118
Reviewed-by: François Doray <fdoray@chromium.org>
Commit-Queue: François Doray <fdoray@chromium.org>
Cr-Commit-Position: refs/heads/master@{#517083}
[modify] https://crrev.com/fe694a6581c8cc68065c305581506e0122c646ae/ui/aura/BUILD.gn
[modify] https://crrev.com/fe694a6581c8cc68065c305581506e0122c646ae/ui/aura/window.cc
[modify] https://crrev.com/fe694a6581c8cc68065c305581506e0122c646ae/ui/aura/window.h
[modify] https://crrev.com/fe694a6581c8cc68065c305581506e0122c646ae/ui/aura/window_delegate.h
[add] https://crrev.com/fe694a6581c8cc68065c305581506e0122c646ae/ui/aura/window_occlusion_tracker.cc
[add] https://crrev.com/fe694a6581c8cc68065c305581506e0122c646ae/ui/aura/window_occlusion_tracker.h
[add] https://crrev.com/fe694a6581c8cc68065c305581506e0122c646ae/ui/aura/window_occlusion_tracker_unittest.cc