Use WeakPtr for BrandcodeConfigFetcher.

The class uses interprocess communication and doesn't have to survive the
parsing result.

Bug: 1023606
Change-Id: I3828b9da3395eee73fd371450349bd062647642a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1911793
Reviewed-by: Balazs Engedy <engedy@chromium.org>
Commit-Queue: Vasilii Sukhanov <vasilii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#714877}
2 files changed