GitLab

Convert all callers to use base::flat_map in the first place, instead of
using std::map and then converting them. Fix link errors along the way.

Change-Id: I34bd7b2c42cfb5cdcd68d4e0880b82633b989697
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1892437Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Reviewed-by: Oksana Zhuravlova <oksamyt@chromium.org>
Reviewed-by: Jenny Zhang <jennyz@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#712876}