Clean up LoginUIService. Remove Singleton behavior from PeopleHandler

components/browser_sync/browser/profile_sync_service.cc

Index: components/browser_sync/browser/profile_sync_service.cc
diff --git a/components/browser_sync/browser/profile_sync_service.cc b/components/browser_sync/browser/profile_sync_service.cc
index 1ec2cd53f9eaa568358d48be6c65aed9f73102c4..a6efcc9f38373bf03b24cc94fcef8b5ef5cf3113 100644
--- a/components/browser_sync/browser/profile_sync_service.cc
+++ b/components/browser_sync/browser/profile_sync_service.cc
@@ -1757,8 +1757,12 @@ void ProfileSyncService::ConfigureDataTypeManager() {
   // start syncing data until the user is done configuring encryption options,
   // etc. ReconfigureDatatypeManager() will get called again once the UI calls
   // SetSetupInProgress(false).
-  if (!CanConfigureDataTypes())
+  if (!CanConfigureDataTypes()) {
+    // If we can't configure the data type manager yet, we should still notify
+    // observers. This is to support multiple setup UIs being open at once.
+    NotifyObservers();
     return;
+  }
 
   bool restart = false;
   if (!data_type_manager_) {