GitLab

Monitor the root window instead of the aura env to determine
when frame sink holder must be cleaned up. It's too late to
cleanup the holder when aura is being shutdown.

Bug: 814908
Test: Close chrome while fast ink view is visible.
Change-Id: Ia807c9469d791e4d8d4973711cf904592bc05471
Reviewed-on: https://chromium-review.googlesource.com/957222Reviewed-by: Vladislav Kaznacheev <kaznacheev@chromium.org>
Commit-Queue: David Reveman <reveman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542179}