[MultiDevice] Do not treat connection latency timeout as failure.

Also mark the corresponding metric as deprecated. See crbug.com/929518
for plans to improve metrics here.

I thouroughly manually tested this change by setting
|kConnectionLatencyTimeoutSeconds| to 0. This allowed me to verify that
even right after attempting to set connection latency, the Bluetooth
API can handle an immediate subsequent attempt to create a GATT
connection. This also allowed me to catch a potential new bug in
OnSetConnectionLatencySuccess() (see comments there for explanation).

Bug: 905724
Change-Id: I26a1ac3111a99212cd73f67507dcc8a19e62c566
Reviewed-on: https://chromium-review.googlesource.com/c/1457729
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Reviewed-by: Jeremy Klein <jlklein@chromium.org>
Commit-Queue: Ryan Hansberry <hansberry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#630454}
4 files changed