GitLab

Use IdentityTestEnvironmentChromeBrowserStateAdaptor instead of manually
creating the browser's state by providing specific factories, and then
use the APIs from IdentityTestEnvironment, instead of SigninManagerBase.

Bug: 890826
Change-Id: Id9d422e002d8fd2edc0ef1ad158f29e95c6dce64
Reviewed-on: https://chromium-review.googlesource.com/c/1318974
Commit-Queue: Mario Sanchez Prada <mario@igalia.com>
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606774}