The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e7ba3d5ac6919434db3f820cb34454291aa7e043

commit e7ba3d5ac6919434db3f820cb34454291aa7e043
Author: Wenzhao Zang <wzang@chromium.org>
Date: Fri Aug 11 17:47:40 2017

Use |SetCacheRenderSurface| for wallpaper blur

Due to the current implementation, there is no explicit 'un-blur' but
the wallpaper widget controller will be recreated. So as a workaround
|SetCacheRenderSurface(false)| is executed every time before the
widget controller is recreated and if blur is needed, it will be set 
to true later, otherwise it will remain false.

It works depending on: 1) when 'cache render surface' is already false,
setting it to false is a no-op, 2) blur can only happen in lock
container, which is true.

Bug: 751248,  753212 
Change-Id: Idce81a3959dfc815d6583bb5aa9e66166ea2d7ae
Reviewed-on: https://chromium-review.googlesource.com/607539
Reviewed-by: Biao She <bshe@chromium.org>
Reviewed-by: David Reveman <reveman@chromium.org>
Commit-Queue: Wenzhao (Colin) Zang <wzang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#493792}
[modify] https://crrev.com/e7ba3d5ac6919434db3f820cb34454291aa7e043/ash/wallpaper/wallpaper_controller.cc
[modify] https://crrev.com/e7ba3d5ac6919434db3f820cb34454291aa7e043/ash/wallpaper/wallpaper_view.cc
[modify] https://crrev.com/e7ba3d5ac6919434db3f820cb34454291aa7e043/ash/wallpaper/wallpaper_widget_controller.cc
[modify] https://crrev.com/e7ba3d5ac6919434db3f820cb34454291aa7e043/ash/wallpaper/wallpaper_widget_controller.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8957a5f2f88c45157d7bed766d6083f27d91bc7b

commit 8957a5f2f88c45157d7bed766d6083f27d91bc7b
Author: Wenzhao Zang <wzang@chromium.org>
Date: Fri Aug 11 20:09:49 2017

Use |SetCacheRenderSurface| for wallpaper blur

Due to the current implementation, there is no explicit 'un-blur' but
the wallpaper widget controller will be recreated. So as a workaround
|SetCacheRenderSurface(false)| is executed every time before the
widget controller is recreated and if blur is needed, it will be set
to true later, otherwise it will remain false.

It works depending on: 1) when 'cache render surface' is already false,
setting it to false is a no-op, 2) blur can only happen in lock
container, which is true.

TBR=wzang@chromium.org

(cherry picked from commit e7ba3d5ac6919434db3f820cb34454291aa7e043)

Bug: 751248,  753212 
Change-Id: Idce81a3959dfc815d6583bb5aa9e66166ea2d7ae
Reviewed-on: https://chromium-review.googlesource.com/607539
Reviewed-by: Biao She <bshe@chromium.org>
Reviewed-by: David Reveman <reveman@chromium.org>
Commit-Queue: Wenzhao (Colin) Zang <wzang@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#493792}
Reviewed-on: https://chromium-review.googlesource.com/612212
Reviewed-by: Wenzhao (Colin) Zang <wzang@chromium.org>
Cr-Commit-Position: refs/branch-heads/3163@{#496}
Cr-Branched-From: ff259bab28b35d242e10186cd63af7ed404fae0d-refs/heads/master@{#488528}
[modify] https://crrev.com/8957a5f2f88c45157d7bed766d6083f27d91bc7b/ash/wallpaper/wallpaper_controller.cc
[modify] https://crrev.com/8957a5f2f88c45157d7bed766d6083f27d91bc7b/ash/wallpaper/wallpaper_view.cc
[modify] https://crrev.com/8957a5f2f88c45157d7bed766d6083f27d91bc7b/ash/wallpaper/wallpaper_widget_controller.cc
[modify] https://crrev.com/8957a5f2f88c45157d7bed766d6083f27d91bc7b/ash/wallpaper/wallpaper_widget_controller.h

Merged approved by the other bug 751248