[Sync] Remove UIDataTypeController

chrome/browser/supervised_user/legacy/supervised_user_sync_service.cc

Index: chrome/browser/supervised_user/legacy/supervised_user_sync_service.cc
diff --git a/chrome/browser/supervised_user/legacy/supervised_user_sync_service.cc b/chrome/browser/supervised_user/legacy/supervised_user_sync_service.cc
index 576787d1110ae9d4934cacbead7642cbb521a566..62b3ce4b58abb70801c3a022ea852e99d367438c 100644
--- a/chrome/browser/supervised_user/legacy/supervised_user_sync_service.cc
+++ b/chrome/browser/supervised_user/legacy/supervised_user_sync_service.cc
@@ -551,8 +551,6 @@ SyncError SupervisedUserSyncService::ProcessSyncChanges(
 void SupervisedUserSyncService::GoogleSignedOut(
     const std::string& account_id,
     const std::string& username) {
-  DCHECK(!sync_processor_);

[Marc Treib, 2016/11/22 09:05:59]

Why this change?

[pavely, 2016/11/22 19:17:52]

GoogleSignedOut is called synchronously to both ProfileSyncService and
SupervisedUserSyncService. ProfileSyncService is lucky to be notified first, it
stops all datatypes and since UI datatypes are notified synchronously as well,
StopSyncing is always called before GoogleSignedOut. This guarantees that
sync_processor_ is cleared before GoogleSignedOut.

After my change StopSyncing is posted on UI thread instead of being directly
called which switches order of notifications. The same would happen if these two
were ordered differently in SigninManagerBase::observer_list. It is still safe
to keep valid sync_processor_. All sync processors are disconnected from backend
during sync shutdown, data passed to sync_processor_ after that will not be
synced or persisted.

[Marc Treib, 2016/11/23 09:16:14]

Thanks for the explanation!

-
   // Clear all data on signout, to avoid supervised users from one custodian
   // appearing in another one's profile.
   prefs_->ClearPref(prefs::kSupervisedUsers);