GitLab

Make all battery info fields optional to be more flexible in the
future, e.g. we may filter some items due to PII filtering policy.

Bug: b:158658869
Test: unit_tests
Change-Id: I65dff7f637db70860060c79dab9b418b809ee73b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2252242
Commit-Queue: Oleh Lamzin <lamzin@google.com>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Giovanni Ortuño Urquidi <ortuno@chromium.org>
Reviewed-by: Mahmoud Gawad <mgawad@google.com>
Cr-Commit-Position: refs/heads/master@{#781811}