GitLab

Adds signout confirmation dialog for Mice based on this design:
https://docs.google.com/presentation/d/1mfVdeJXk2hLXjyzOp9TBIx0E7-7jmuoN1-4oB6dYd5I/edit#slide=id.gaea85d524f_2_0

iPad:
https://drive.google.com/file/d/1UAS0L-ANTaIDEN2FFh2mgAiwKe-ksQ5U
https://drive.google.com/file/d/1kQJoi6Vqe-xEsbLokmePAlAWU5kNl99T
https://drive.google.com/file/d/1DUou8tJ1UR54lQtI2Zzi5smJ3aoUbyXX

iPhone:
https://drive.google.com/file/d/13TPquf7Z8HbdkCDmQhXnyqwP0VQGxwTp
https://drive.google.com/file/d/1UjLwwkEk4RKnkDfX-7BSLmfqo6Lj1Ewd
https://drive.google.com/file/d/1aykwVlgT3npD3DQkMCPWJm3hYiMeJfLx

Bug: 1166148
Change-Id: Ica58a513ee216d79f4994d155a4941ea5fdbe3d4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2627401
Commit-Queue: Jérôme Lebel <jlebel@chromium.org>
Reviewed-by: Nohemi Fernandez <fernandex@chromium.org>
Auto-Submit: Jérôme Lebel <jlebel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#846086}