The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/91d2e90881fc404976e1aa462d1d6a1681c0d687

commit 91d2e90881fc404976e1aa462d1d6a1681c0d687
Author: Qiang Xu <warx@chromium.org>
Date: Wed Jul 05 20:47:09 2017

cros: Get wallpaper prominent colors for closed searchbox view

changes:
In crrev.com/2943333003, multiple/six wallpaper prominent colors
are extracted in ash::WallpaperController. This CL wants to get dark
muted color and light vibrant color for app_list::SearchBoxView.
(1) Define remote observer mojo::WallpaperObserver for this purpose.
(2) Make AppListViewDelegate in chrome/ as a observer, and notify
wallpaper color changes for search box model. And add
WallpaperProminentColorsChanged() API in SearchBoxModelObserver to
update the search box view.
(3) if wallpaper prominent color is available, using dark muted color
extracted form the wallpaper for G, microphone as well as the label;
using (light vibrant color 100% + #FFF 70%) at 100% opacity for
searchbox background color.

flag, screenshot: https://screenshot.googleplex.com/awwbVHnjDPV

R: xiyuan@chromium.org, xdai@chromium.org, jamescook@chromium.org
Bug:  733391 ,  732492 
TEST: tested with and without --enable-features=EnableFullscreenAppList
Change-Id: I07890f48ea02518bbfd948035d9e4d4a01d56c65
Reviewed-on: https://chromium-review.googlesource.com/550320
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Reviewed-by: Xiaoqian Dai <xdai@chromium.org>
Commit-Queue: Qiang(Joe) Xu <warx@chromium.org>
Cr-Commit-Position: refs/heads/master@{#484344}
[modify] https://crrev.com/91d2e90881fc404976e1aa462d1d6a1681c0d687/ash/public/interfaces/wallpaper.mojom
[modify] https://crrev.com/91d2e90881fc404976e1aa462d1d6a1681c0d687/ash/wallpaper/wallpaper_controller.cc
[modify] https://crrev.com/91d2e90881fc404976e1aa462d1d6a1681c0d687/ash/wallpaper/wallpaper_controller.h
[modify] https://crrev.com/91d2e90881fc404976e1aa462d1d6a1681c0d687/ash/wallpaper/wallpaper_controller_unittest.cc
[modify] https://crrev.com/91d2e90881fc404976e1aa462d1d6a1681c0d687/chrome/browser/ui/app_list/app_list_view_delegate.cc
[modify] https://crrev.com/91d2e90881fc404976e1aa462d1d6a1681c0d687/chrome/browser/ui/app_list/app_list_view_delegate.h
[modify] https://crrev.com/91d2e90881fc404976e1aa462d1d6a1681c0d687/components/wallpaper/BUILD.gn
[add] https://crrev.com/91d2e90881fc404976e1aa462d1d6a1681c0d687/components/wallpaper/wallpaper_color_profile.h
[modify] https://crrev.com/91d2e90881fc404976e1aa462d1d6a1681c0d687/ui/app_list/BUILD.gn
[modify] https://crrev.com/91d2e90881fc404976e1aa462d1d6a1681c0d687/ui/app_list/search_box_model.cc
[modify] https://crrev.com/91d2e90881fc404976e1aa462d1d6a1681c0d687/ui/app_list/search_box_model.h
[modify] https://crrev.com/91d2e90881fc404976e1aa462d1d6a1681c0d687/ui/app_list/search_box_model_observer.h
[modify] https://crrev.com/91d2e90881fc404976e1aa462d1d6a1681c0d687/ui/app_list/views/search_box_view.cc
[modify] https://crrev.com/91d2e90881fc404976e1aa462d1d6a1681c0d687/ui/app_list/views/search_box_view.h