Migration of testing scripts in tools/ to libv2

tools/testing/dart/drt_updater.dart

Index: tools/testing/dart/drt_updater.dart
diff --git a/tools/testing/dart/drt_updater.dart b/tools/testing/dart/drt_updater.dart
index e6645dfda2aaebbc99b8349c5966d6f9dcd1fb73..afe90d5dac0a75b6c1f4657a98afa924616c3245 100644
--- a/tools/testing/dart/drt_updater.dart
+++ b/tools/testing/dart/drt_updater.dart
@@ -4,6 +4,7 @@
 
 library drt_updater;
 
+import "dart:async";
 import "dart:io";
 
 import "test_suite.dart";
@@ -27,11 +28,10 @@ class _DartiumUpdater {
       print('Updating $name.');
       onUpdated = [() {updated = true;} ];
       _updatingProcess = Process.run('python', _getUpdateCommand);
-      _updatingProcess.handleException((e) {
+      _updatingProcess.then(_onUpdatedHandler).catchError((e) {
         print("Error starting $script process: $e");
         return false;
       });
-      _updatingProcess.then(_onUpdatedHandler);
     }
   }