Added new DriveNotificationObserver interface which all observers of Google Drive invalidations sho…

chrome/browser/sync_file_system/drive_file_sync_service.cc

Index: chrome/browser/sync_file_system/drive_file_sync_service.cc
diff --git a/chrome/browser/sync_file_system/drive_file_sync_service.cc b/chrome/browser/sync_file_system/drive_file_sync_service.cc
index c7a12a71ac23981eb08db43801ebdfccd40e0642..ff0da3f35116398d432ba4827a035069bec86bfc 100644
--- a/chrome/browser/sync_file_system/drive_file_sync_service.cc
+++ b/chrome/browser/sync_file_system/drive_file_sync_service.cc
@@ -2179,6 +2179,10 @@ void DriveFileSyncService::MaybeStartFetchChanges() {
   }
 }
 
+void DriveFileSyncService::CheckForUpdates() {
+  MaybeStartFetchChanges();
+}
+
 void DriveFileSyncService::FetchChangesForIncrementalSync() {
   scoped_ptr<TaskToken> token(GetToken(FROM_HERE, TASK_TYPE_DRIVE,
                                        "Fetching remote change list"));