[Background Sync] Add proper error status to API calls and callbacks

content/child/background_sync/background_sync_provider.h

Index: content/child/background_sync/background_sync_provider.h
diff --git a/content/child/background_sync/background_sync_provider.h b/content/child/background_sync/background_sync_provider.h
index 93d4fefbd732db5e6b161b7ded6305d2d9665859..a4b14235419f9f1828a4b869e27fe06710663f9d 100644
--- a/content/child/background_sync/background_sync_provider.h
+++ b/content/child/background_sync/background_sync_provider.h
@@ -52,12 +52,14 @@ class BackgroundSyncProvider : public blink::WebSyncProvider {
   // Callback handlers
   void RegisterCallback(
       scoped_ptr<blink::WebSyncRegistrationCallbacks> callbacks,
+      BackgroundSyncError error,
       const SyncRegistrationPtr& options);
   void UnregisterCallback(
       scoped_ptr<blink::WebSyncUnregistrationCallbacks> callbacks,
-      bool success);
+      BackgroundSyncError error);
   void GetRegistrationsCallback(
       scoped_ptr<blink::WebSyncGetRegistrationsCallbacks> callbacks,
+      BackgroundSyncError error,
       const mojo::Array<SyncRegistrationPtr>& registrations);
 
   // Helper method that returns an initialized BackgroundSyncServicePtr.