GitLab

Drop set_owned_by_client from NotificationViewMDTest Tests

The widget assumes ownership of the notification view in
NotificationViewMDTest.

Effort was also made to remove as many direct pointers to the widget
as possible to demonstrate the linkage.

BUG=1044687

Change-Id: I010d2cf742c043b5e257f22abb6a4688e3707877
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2203019
Commit-Queue: Tim Song <tengs@chromium.org>
Auto-Submit: Robert Liao <robliao@chromium.org>
Reviewed-by: Tim Song <tengs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#769043}