Chromium change: https://source.chromium.org/chromium/chromium/src/+/6853852a6e345346bb9b0578c83b5b7989e8b3ad [Android][Signin] Move sign-in operation to bottom sheet mediator The main goal of this CL is to move the sign-in related operations and the use of SigninManager from the AccountPickerDelegate implementations to AccountPickerBottomSheetMediator. It also add a sign-out operation right before sign-in if there's an existing account. This behavior was previously implemented only for the web sign-in entry point, but it also makes sense for the other flows. The SignoutReason enum description is updated accordingly to state it's not only used by the web-signin anymore. The tests are updated accordingly. Bug: 431198423, 40646656 Change-Id: I9ac9f3410cba714d16a1dd02b46f1d69afcf0eb2 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6759794