GitLab

This cl allows client to set custom_frame_view color.
Changes:
1. Add OnWindowPropertyChanged to CustomFrameViewAshWindowStateDelegate.
2. Client can set custom_frame_view color by setting window property
aura::client::kTopViewColor.

Bug: 811159, 768932
Test: CustomFrameViewAshTest.KTopViewColor and manually test color update.
Change-Id: Ic2306c399b0d4cda88ffb0f96c48a15e3e6f430b
Reviewed-on: https://chromium-review.googlesource.com/912518
Commit-Queue: Tao Wu <wutao@chromium.org>
Reviewed-by: Mitsuru Oshima (In Tokyo) <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#536748}