Desktop PWAs: Add badge record keeping to the badging service.

This CL introduces a per-Profile BadgeManager that keeps a record of
badge contents for installed PWAs and handles dispatching badge changes
via. a delegate.

This CL doesn't add any UI support.

Bug: 719176
Change-Id: I4779c1ec5486ee1c71e35f1a4116580fdaefe7da
Reviewed-on: https://chromium-review.googlesource.com/c/1170451
Reviewed-by: Matt Giuca <mgiuca@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Eric Stevenson <estevenson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#614690}
12 files changed