Attached screenshot

Deleted: IMG_20160629_162637.jpg 3.1 MB

	IMG_20160629_162637.jpg 3.1 MB View Download

Moving this nonessential bug to the next milestone.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Handing off to varkha@ for triage.

Is this significantly different when setting --ash-md=disabled? Seems like the problem is pre-existing but would be great to know if the threshold when this starts happening has regressed.

 Issue 624606  has been merged into this issue.

Able to reproduce the issue with setting --ash-md=disabled. When this flag is disabled, the shelf items are missing even after exiting from overview mode .

Thanks, #7. I will punt this to M-54 to see if we can improve anything.

For me 17 windows are fine. Anything after that; craziness ensues 

I have a draft CL at https://codereview.chromium.org/2146323004/ that should improve the situation albeit at a cost of no longer hiding the window headers (but hiding the window controls) once the number of windows is large (>10).
I would like to get a feel if this is an acceptable trade-off.
That CL should also fix  issue 626851 , at least when there are many windows.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d8748a3907d55ade9282b8cf4d0993ac9ee5ab66

commit d8748a3907d55ade9282b8cf4d0993ac9ee5ab66
Author: varkha <varkha@chromium.org>
Date: Tue Jul 19 16:03:45 2016

[ash-md] Improves smoothness with many windows in overview

Experimentally, most of the animation cost was coming from having window
shapes (used to mask the window header) and from using rounded rectangle
masks.
This CL disables both those performance hogs when there are more than
certain number of windows in the overview mode (controlled via flags).
Default is set to hardcoded 10.
It also makes sure that window controls (minimize / resize / close) are
hidden when in overview mode for custom and panel frames.

New flags are introduced:

--ash-max-previews-to-use-mask=<number>
Maximum number of preview windows in overview mode that can use masks to
hide window headers and use rounded corners. Use -1 to set to unlimited.

--ash-max-previews-to-use-shape=<number>
Maximum number of preview windows in overview mode that can use shapes to
hide window headers. Use -1 to set to unlimited.

BUG= 626851 
BUG= 624608 

Review-Url: https://codereview.chromium.org/2146323004
Cr-Commit-Position: refs/heads/master@{#406286}

[modify] https://crrev.com/d8748a3907d55ade9282b8cf4d0993ac9ee5ab66/ash/common/ash_switches.cc
[modify] https://crrev.com/d8748a3907d55ade9282b8cf4d0993ac9ee5ab66/ash/common/ash_switches.h
[modify] https://crrev.com/d8748a3907d55ade9282b8cf4d0993ac9ee5ab66/ash/common/wm/overview/scoped_transform_overview_window.cc
[modify] https://crrev.com/d8748a3907d55ade9282b8cf4d0993ac9ee5ab66/ash/common/wm/overview/scoped_transform_overview_window.h
[modify] https://crrev.com/d8748a3907d55ade9282b8cf4d0993ac9ee5ab66/ash/common/wm/overview/window_grid.cc
[modify] https://crrev.com/d8748a3907d55ade9282b8cf4d0993ac9ee5ab66/ash/common/wm/overview/window_selector_item.cc
[modify] https://crrev.com/d8748a3907d55ade9282b8cf4d0993ac9ee5ab66/ash/common/wm/overview/window_selector_item.h
[modify] https://crrev.com/d8748a3907d55ade9282b8cf4d0993ac9ee5ab66/ash/frame/custom_frame_view_ash.cc
[modify] https://crrev.com/d8748a3907d55ade9282b8cf4d0993ac9ee5ab66/ash/wm/panels/panel_frame_view.cc
[modify] https://crrev.com/d8748a3907d55ade9282b8cf4d0993ac9ee5ab66/ash/wm/panels/panel_frame_view.h
[modify] https://crrev.com/d8748a3907d55ade9282b8cf4d0993ac9ee5ab66/chrome/app/generated_resources.grd
[modify] https://crrev.com/d8748a3907d55ade9282b8cf4d0993ac9ee5ab66/chrome/browser/about_flags.cc
[modify] https://crrev.com/d8748a3907d55ade9282b8cf4d0993ac9ee5ab66/tools/metrics/histograms/histograms.xml

Would be good to merge CL in #12 into M-53.

Your change meets the bar and is auto-approved for M53 (branch: 2785)

This issue has been approved for a merge. Please merge the fix to any appropriate branches as soon as possible!

If all merges have been completed, please remove any remaining Merge-Approved labels from this issue.

Thanks for your time! To disable nags, add the Disable-Nags label.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/fbfb5afbb61eac2a18e6b210ec4f40162357f612

commit fbfb5afbb61eac2a18e6b210ec4f40162357f612
Author: Valery Arkhangorodsky <varkha@chromium.org>
Date: Tue Jul 26 22:51:04 2016

[ash-md] Improves smoothness with many windows in overview

Experimentally, most of the animation cost was coming from having window
shapes (used to mask the window header) and from using rounded rectangle
masks.
This CL disables both those performance hogs when there are more than
certain number of windows in the overview mode (controlled via flags).
Default is set to hardcoded 10.
It also makes sure that window controls (minimize / resize / close) are
hidden when in overview mode for custom and panel frames.

New flags are introduced:

--ash-max-previews-to-use-mask=<number>
Maximum number of preview windows in overview mode that can use masks to
hide window headers and use rounded corners. Use -1 to set to unlimited.

--ash-max-previews-to-use-shape=<number>
Maximum number of preview windows in overview mode that can use shapes to
hide window headers. Use -1 to set to unlimited.

BUG= 626851 
BUG= 624608 

Review-Url: https://codereview.chromium.org/2146323004
Cr-Commit-Position: refs/heads/master@{#406286}
(cherry picked from commit d8748a3907d55ade9282b8cf4d0993ac9ee5ab66)

Review URL: https://codereview.chromium.org/2184543005 .

Cr-Commit-Position: refs/branch-heads/2785@{#365}
Cr-Branched-From: 68623971be0cfc492a2cb0427d7f478e7b214c24-refs/heads/master@{#403382}

[modify] https://crrev.com/fbfb5afbb61eac2a18e6b210ec4f40162357f612/ash/common/ash_switches.cc
[modify] https://crrev.com/fbfb5afbb61eac2a18e6b210ec4f40162357f612/ash/common/ash_switches.h
[modify] https://crrev.com/fbfb5afbb61eac2a18e6b210ec4f40162357f612/ash/common/wm/overview/scoped_transform_overview_window.cc
[modify] https://crrev.com/fbfb5afbb61eac2a18e6b210ec4f40162357f612/ash/common/wm/overview/scoped_transform_overview_window.h
[modify] https://crrev.com/fbfb5afbb61eac2a18e6b210ec4f40162357f612/ash/common/wm/overview/window_grid.cc
[modify] https://crrev.com/fbfb5afbb61eac2a18e6b210ec4f40162357f612/ash/common/wm/overview/window_selector_item.cc
[modify] https://crrev.com/fbfb5afbb61eac2a18e6b210ec4f40162357f612/ash/common/wm/overview/window_selector_item.h
[modify] https://crrev.com/fbfb5afbb61eac2a18e6b210ec4f40162357f612/ash/frame/custom_frame_view_ash.cc
[modify] https://crrev.com/fbfb5afbb61eac2a18e6b210ec4f40162357f612/ash/wm/panels/panel_frame_view.cc
[modify] https://crrev.com/fbfb5afbb61eac2a18e6b210ec4f40162357f612/ash/wm/panels/panel_frame_view.h
[modify] https://crrev.com/fbfb5afbb61eac2a18e6b210ec4f40162357f612/chrome/app/generated_resources.grd
[modify] https://crrev.com/fbfb5afbb61eac2a18e6b210ec4f40162357f612/chrome/browser/about_flags.cc
[modify] https://crrev.com/fbfb5afbb61eac2a18e6b210ec4f40162357f612/tools/metrics/histograms/histograms.xml

 Issue 626851  has been merged into this issue.

Valery can this be moved to M-55 or is there still something you plan to fix and merge back into 54?

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f5d0098acc9a8167409476627eae3e91d94e8cac

commit f5d0098acc9a8167409476627eae3e91d94e8cac
Author: varkha <varkha@chromium.org>
Date: Fri Sep 09 22:06:20 2016

[ash-md] Fades overview header in and out

This change installs an additional header on top of the real window's header and animates its bounds and opacity such that it appears to take over the real header. Only once the "fake" header is opaque a mask or alpha shape is applied to the window to hide its original header after which the "fake" header becomes translucent to conform to MD overview mode spec.

This creates a visually smoother transition into overview mode than before.

Special care is taken to animate the "fake" header in case when the window is restored for the overview mode from the minimized state and is thus animated from the shelf item.

BUG= 624608 ,  645076 
TEST=Most changes are only really visible under a great slow-down but watching closely the files app header transform into overview mode should be much less abrupt.

Review-Url: https://codereview.chromium.org/2239233002
Cr-Commit-Position: refs/heads/master@{#417728}

[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/aura/wm_window_aura.cc
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/aura/wm_window_aura.h
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/common/frame/custom_frame_view_ash.cc
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/common/frame/default_header_painter.cc
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/common/frame/default_header_painter.h
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/common/frame/header_view.cc
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/common/frame/header_view.h
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/common/wm/overview/overview_animation_type.h
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/common/wm/overview/scoped_overview_animation_settings.h
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/common/wm/overview/scoped_transform_overview_window.cc
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/common/wm/overview/scoped_transform_overview_window.h
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/common/wm/overview/window_grid.cc
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/common/wm/overview/window_grid.h
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/common/wm/overview/window_selector_item.cc
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/common/wm/overview/window_selector_item.h
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/common/wm_window.h
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/common/wm_window_property.h
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/mus/bridge/wm_window_mus.cc
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/mus/bridge/wm_window_mus.h
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/wm/overview/scoped_overview_animation_settings_aura.cc
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/wm/overview/scoped_overview_animation_settings_aura.h
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/wm/overview/window_selector_unittest.cc
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ash/wm/panels/panel_frame_view.cc
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/chrome/browser/ui/views/frame/browser_non_client_frame_view_ash.cc
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ui/aura/client/aura_constants.cc
[modify] https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac/ui/aura/client/aura_constants.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/758e34e4a30be65c2cedf5fb2a893fa3a87596f0

commit 758e34e4a30be65c2cedf5fb2a893fa3a87596f0
Author: dmurph <dmurph@chromium.org>
Date: Sat Sep 10 01:50:58 2016

Revert of [ash-md] Fades overview header in and out (patchset #17 id:400001 of https://codereview.chromium.org/2239233002/ )

Reason for revert:
This is causing a use-after-free and crashing stuff :(

BUG= 645708 

Original issue's description:
> [ash-md] Fades overview header in and out
>
> This change installs an additional header on top of the real window's header and animates its bounds and opacity such that it appears to take over the real header. Only once the "fake" header is opaque a mask or alpha shape is applied to the window to hide its original header after which the "fake" header becomes translucent to conform to MD overview mode spec.
>
> This creates a visually smoother transition into overview mode than before.
>
> Special care is taken to animate the "fake" header in case when the window is restored for the overview mode from the minimized state and is thus animated from the shelf item.
>
> BUG= 624608 ,  645076 
> TEST=Most changes are only really visible under a great slow-down but watching closely the files app header transform into overview mode should be much less abrupt.
>
> Committed: https://crrev.com/f5d0098acc9a8167409476627eae3e91d94e8cac
> Cr-Commit-Position: refs/heads/master@{#417728}

TBR=sky@chromium.org,bruthig@chromium.org,varkha@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG= 624608 ,  645076 

Review-Url: https://codereview.chromium.org/2329433003
Cr-Commit-Position: refs/heads/master@{#417796}

[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/aura/wm_window_aura.cc
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/aura/wm_window_aura.h
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/common/frame/custom_frame_view_ash.cc
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/common/frame/default_header_painter.cc
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/common/frame/default_header_painter.h
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/common/frame/header_view.cc
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/common/frame/header_view.h
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/common/wm/overview/overview_animation_type.h
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/common/wm/overview/scoped_overview_animation_settings.h
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/common/wm/overview/scoped_transform_overview_window.cc
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/common/wm/overview/scoped_transform_overview_window.h
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/common/wm/overview/window_grid.cc
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/common/wm/overview/window_grid.h
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/common/wm/overview/window_selector_item.cc
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/common/wm/overview/window_selector_item.h
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/common/wm_window.h
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/common/wm_window_property.h
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/mus/bridge/wm_window_mus.cc
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/mus/bridge/wm_window_mus.h
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/wm/overview/scoped_overview_animation_settings_aura.cc
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/wm/overview/scoped_overview_animation_settings_aura.h
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/wm/overview/window_selector_unittest.cc
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ash/wm/panels/panel_frame_view.cc
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/chrome/browser/ui/views/frame/browser_non_client_frame_view_ash.cc
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ui/aura/client/aura_constants.cc
[modify] https://crrev.com/758e34e4a30be65c2cedf5fb2a893fa3a87596f0/ui/aura/client/aura_constants.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ebc9b9dfb7982cf069897b750a76231ab5bb2e31

commit ebc9b9dfb7982cf069897b750a76231ab5bb2e31
Author: varkha <varkha@chromium.org>
Date: Mon Sep 12 20:07:30 2016

Reland of [ash-md] Fades overview header in and out

This change installs an additional header on top of the real window's header and animates its bounds and opacity such that it appears to take over the real header. Only once the "fake" header is opaque a mask or alpha shape is applied to the window to hide its original header after which the "fake" header becomes translucent to conform to MD overview mode spec.

This creates a visually smoother transition into overview mode than before.

Special care is taken to animate the "fake" header in case when the window is restored for the overview mode from the minimized state and is thus animated from the shelf item.

---

This relands https://codereview.chromium.org/2239233002/ and
reverts commit 758e34e4a30be65c2cedf5fb2a893fa3a87596f0.

Corrects lifetime manipulation of the child views after their
ownership it taken over by a CleanupAnimationObserver.

BUG= 624608 ,  645076 ,  645708 
TEST=Most changes are only really visible under a great slow-down but watching closely the files app header transform into overview mode should be much less abrupt.

Review-Url: https://codereview.chromium.org/2336673002
Cr-Commit-Position: refs/heads/master@{#418017}

[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/aura/wm_window_aura.cc
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/aura/wm_window_aura.h
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/common/frame/custom_frame_view_ash.cc
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/common/frame/default_header_painter.cc
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/common/frame/default_header_painter.h
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/common/frame/header_view.cc
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/common/frame/header_view.h
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/common/wm/overview/overview_animation_type.h
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/common/wm/overview/scoped_overview_animation_settings.h
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/common/wm/overview/scoped_transform_overview_window.cc
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/common/wm/overview/scoped_transform_overview_window.h
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/common/wm/overview/window_grid.cc
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/common/wm/overview/window_grid.h
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/common/wm/overview/window_selector_item.cc
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/common/wm/overview/window_selector_item.h
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/common/wm_window.h
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/common/wm_window_property.h
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/mus/bridge/wm_window_mus.cc
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/mus/bridge/wm_window_mus.h
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/wm/overview/scoped_overview_animation_settings_aura.cc
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/wm/overview/scoped_overview_animation_settings_aura.h
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/wm/overview/window_selector_unittest.cc
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ash/wm/panels/panel_frame_view.cc
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/chrome/browser/ui/views/frame/browser_non_client_frame_view_ash.cc
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ui/aura/client/aura_constants.cc
[modify] https://crrev.com/ebc9b9dfb7982cf069897b750a76231ab5bb2e31/ui/aura/client/aura_constants.h

<triage>@varkha, what's the status of this?</triage>

I am hoping that https://codereview.chromium.org/2633643002/ (in review) and https://codereview.chromium.org/2627153006/ (landed as r443342) would have reduced texture memory consumption to make this better. Will need to wait to confirm on canary.

Updating milestone to m-57.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d4824ca45ebcccbdd2869310f366c1b178a4be85

commit d4824ca45ebcccbdd2869310f366c1b178a4be85
Author: varkha <varkha@chromium.org>
Date: Tue Jan 17 20:39:00 2017

[ash-md] Reduces dimensions of texture layers in overview mode

This CL simplifies the view structure of the visible items in overview
mode and reduces the dimensions of the texture layers used.

Previously each item was a widget (with a default texture layer)
that was sllightly bigger than the window and had a LabelButton covering
most of the area with a custom background. That background was only made
non-transparent in a caption above the window so the texture layer was
in fact unnecessarily large.
With this change the widget is created with a ui::LAYER_NOT_DRAWN layer
and only the narrow visible background behind the caption has a texture
layer (necessary to implement rounded corners for the visible caption).
The views structure has also been simplified. The view is covered by a
simple button (to capture events) and a simple Label is used in place
of the LabelButton.

BUG= 537050 ,  624608 
TEST=NONE - no visible change

Review-Url: https://codereview.chromium.org/2633643002
Cr-Commit-Position: refs/heads/master@{#444129}

[modify] https://crrev.com/d4824ca45ebcccbdd2869310f366c1b178a4be85/ash/ash_strings.grd
[modify] https://crrev.com/d4824ca45ebcccbdd2869310f366c1b178a4be85/ash/common/wm/overview/window_selector_item.cc
[modify] https://crrev.com/d4824ca45ebcccbdd2869310f366c1b178a4be85/ash/common/wm/overview/window_selector_item.h
[modify] https://crrev.com/d4824ca45ebcccbdd2869310f366c1b178a4be85/ash/wm/overview/window_selector_unittest.cc

I won't be able to work on this anytime soon so returning to the queue for triage.

wutao@ could you please try repro? I wasn't able to.

This looks like missing tiles when the memory is under stress, which depends what device you test. We probably cannot do too much in addition to reduce the memory usage for the overview mode.

varkha@ made some changes to improve the memory usage. Maybe we can close this by "Fixed"?

We had many changes recently to overview mode. I will close this bug for now.
Please feel free to reopen it or create a new one.

Thanks.