GitLab

SystemTrayNotifier will be removed, so move the observer list direclty
into TrayBluetoothHelper.

Bug: 882346
Change-Id: I316a43cc98d879003e378e01994e40038e557f93
Reviewed-on: https://chromium-review.googlesource.com/c/1343588Reviewed-by: Tetsui Ohkubo <tetsui@chromium.org>
Commit-Queue: Giovanni Ortuño Urquidi <ortuno@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609811}