🤝 Notify user that a Trusted Web Activity is running in Chrome.

Notify the user via Toast that an opened Trusted Web Activity is part
of Chrome and therefore will have access to their cookies, autofill
data, etc.

This is shown at most once per week for a single app.

Bug: 813100
Change-Id: I7f921637ffa042ff4d0f076ad4ca007708f06879
Reviewed-on: https://chromium-review.googlesource.com/1097399
Commit-Queue: Peter Conn <peconn@chromium.org>
Reviewed-by: Benoit L <lizeb@chromium.org>
Reviewed-by: Bernhard Bauer <bauerb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#566784}
6 files changed