The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/30f6310f7e47ff55d3e06e39992147d3533deea8

commit 30f6310f7e47ff55d3e06e39992147d3533deea8
Author: Weidong Guo <weidongg@chromium.org>
Date: Tue Jul 18 20:35:44 2017

Make pagination switcher vertically centered

Changes:
1. Make the dots of pagination switcher centered vertically on
AppsGridView no matter their number.

Spec: https://screenshot.googleplex.com/QHkyJRGmz46
Screenshot: https://screenshot.googleplex.com/MLduTvsXwcf

BUG= 741007 

Change-Id: I5305267af35b21ba3446424c3bedc8d2eab8615d
Reviewed-on: https://chromium-review.googlesource.com/576249
Reviewed-by: Yury Khmel <khmel@chromium.org>
Commit-Queue: Weidong Guo <weidongg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#487592}
[modify] https://crrev.com/30f6310f7e47ff55d3e06e39992147d3533deea8/ui/app_list/views/apps_grid_view.cc

The 24px horizontal padding is not implemented yet.

I once removed some code about it in: https://chromium-review.googlesource.com/c/551484/, as it affects all apps layouting.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/94bff0938b301380ed4dd83a5086ffe1ccedebb4

commit 94bff0938b301380ed4dd83a5086ffe1ccedebb4
Author: Weidong Guo <weidongg@chromium.org>
Date: Thu Jul 20 18:00:00 2017

Adjust the page switcher's position

Changes:
1. Enlarges the width of the AppsGridView to make 24px horizontal
padding for page switcher.
2. In the meanwhile, keeps the AppsGridView horizontally centered by
adding equal space to left and right side.

Specs: https://screenshot.googleplex.com/vdLmFvaJSdR
Screenshot: https://screenshot.googleplex.com/SWec2Jeqhon

BUG= 741007 

Change-Id: If74cc65099385580b8955825febcd39526a05992
Reviewed-on: https://chromium-review.googlesource.com/578723
Commit-Queue: Weidong Guo <weidongg@chromium.org>
Reviewed-by: Yury Khmel <khmel@chromium.org>
Reviewed-by: Qiang(Joe) Xu <warx@chromium.org>
Cr-Commit-Position: refs/heads/master@{#488305}
[modify] https://crrev.com/94bff0938b301380ed4dd83a5086ffe1ccedebb4/ui/app_list/app_list_constants.cc
[modify] https://crrev.com/94bff0938b301380ed4dd83a5086ffe1ccedebb4/ui/app_list/app_list_constants.h
[modify] https://crrev.com/94bff0938b301380ed4dd83a5086ffe1ccedebb4/ui/app_list/views/apps_grid_view.cc
[modify] https://crrev.com/94bff0938b301380ed4dd83a5086ffe1ccedebb4/ui/app_list/views/folder_header_view.cc