Replace FOR_EACH_OBSERVER in components/drive with range-based for

components/drive/drive_app_registry.cc

Index: components/drive/drive_app_registry.cc
diff --git a/components/drive/drive_app_registry.cc b/components/drive/drive_app_registry.cc
index d0861b0b85fc6c0a30a68aeea845f9608f9b37b3..f6cbc502cdf487607dc11f8af78947e6d531b176 100644
--- a/components/drive/drive_app_registry.cc
+++ b/components/drive/drive_app_registry.cc
@@ -189,9 +189,8 @@ void DriveAppRegistry::UpdateFromAppList(const google_apis::AppList& app_list) {
     AddAppSelectorList(app.secondary_file_extensions(), id, &extension_map_);
   }
 
-  FOR_EACH_OBSERVER(DriveAppRegistryObserver,
-                    observers_,
-                    OnDriveAppRegistryUpdated());
+  for (auto& observer : observers_)
+    observer.OnDriveAppRegistryUpdated();
 }
 
 void DriveAppRegistry::AddObserver(DriveAppRegistryObserver* observer) {