Extract FakeDeviceInfoTracker and use it in tests.

This extracts a FakeDeviceInfoTracker that was implemented in multiple
places already and uses it instead.

Bug: 958016
Change-Id: Ia7d01008af5925cfa8ad0b50bc14d10ae07d8ee7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1662450
Commit-Queue: sebsg <sebsg@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Reviewed-by: sebsg <sebsg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#669805}
8 files changed