GitLab

Adding:
  +[SigninEarlGreyUI tapAddAccountButton] helper
  chrome_test_util::UnifiedConsentAddAccountButton()

Needed for:
  crrev.com/i/1148950
  crrev.com/i/1366448

Bug: 944180
Change-Id: Ifc321fb59a86a89111a3c32be62665da4d1e45ea
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1649155
Commit-Queue: Jérôme Lebel <jlebel@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#667365}