GitLab

HoldingSpaceTray observes holding space bubble widget, but it was not
removing itself from the widget observer list if the bubble got closed
without going through HoldingpaceTray::CloseBubble.

Without this, holding space tray unittests crash on teardown unless the
tray bubble is closed.

Bug: None
Change-Id: If01f7b23e0268734ba178c566f961e645525438f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2504214
Commit-Queue: Toni Baržić <tbarzic@chromium.org>
Reviewed-by: David Black <dmblack@google.com>
Cr-Commit-Position: refs/heads/master@{#823058}