GitLab

This CL moves the method called by native code launchSigninActivity()
from SigninPromoUtil to SigninBridge.

Bug: 1165772
Change-Id: Id684316cd759379235651511d34216fcbb74337d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2632950Reviewed-by: Marc Treib <treib@chromium.org>
Reviewed-by: Boris Sazonov <bsazonov@chromium.org>
Commit-Queue: Alice Wang <aliceywang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#844723}