GitLab

crrev.com/c/1478878 started exposing the web signout state as a
DisableReason in the SyncService API. This caused a number of bugs when
kStopSyncInPausedState was enabled, the main reason being that the
presence of a DisableReason causes the class to consider
sync-the-feature as disabled.

The CL removes the DISABLE_REASON_PAUSED and adds a new transport state
PAUSED. IsEngineAllowedToStart() now checks that a) no reason to disable
sync-the-feature exists; b) sync is not in the paused state.

The feature flag is still kept as DISABLED_BY_DEFAULT, pending
experimentation on Canary/Dev.

TBR=parastoog@google.com

Bug: 906995
Change-Id: I533da440835330ffbbbaaf3862b9343f16149f78
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2302149
Commit-Queue: Victor Vianna <victorvianna@google.com>
Reviewed-by: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#790765}