GitLab

This CL moves logSigninStartUserAction to SigninMetricsUtils to group
the signin metrics logging methods in one place.

Bug: 1163476
Change-Id: I515a2c04f4bac3541a0a3bcee4097c3dabab95cf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2611715Reviewed-by: Wenyu Fu <wenyufu@chromium.org>
Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
Reviewed-by: Tanmoy Mollik <triploblastic@chromium.org>
Commit-Queue: Alice Wang <aliceywang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#844008}