Treat SyncCredentialsLost as an auth error

chrome/browser/sync/profile_sync_service.h

Index: chrome/browser/sync/profile_sync_service.h
diff --git a/chrome/browser/sync/profile_sync_service.h b/chrome/browser/sync/profile_sync_service.h
index 0007b6ac951e582079b6282514a64d3df15d8cdd..362ed370ea81e1f3a0d7fdce7e1a71a06bf3289d 100644
--- a/chrome/browser/sync/profile_sync_service.h
+++ b/chrome/browser/sync/profile_sync_service.h
@@ -180,9 +180,16 @@ class ProfileSyncService : public browser_sync::SyncFrontend,
 
   void RegisterAuthNotifications();
 
+  // Returns true if sync is enabled/not suppressed and the user is logged in.
+  // (being logged in does not mean that tokens are available - tokens may
+  // be missing because they have not loaded yet, or because they were deleted
+  // due to http://crbug.com/121755).
+  // Virtual to enable mocking in tests.
+  virtual bool IsSyncEnabledAndLoggedIn();
+
   // Return whether all sync tokens are loaded and available for the backend to
   // start up. Virtual to enable mocking in tests.
-  virtual bool AreCredentialsAvailable();
+  virtual bool IsSyncTokenAvailable();
 
   // Registers a data type controller with the sync service.  This
   // makes the data type controller available for use, it does not