Add --step_name option to test.dart.

dart/tools/testing/dart/test_runner.dart

Index: dart/tools/testing/dart/test_runner.dart
diff --git a/dart/tools/testing/dart/test_runner.dart b/dart/tools/testing/dart/test_runner.dart
index e349dfc64f83c1a4d696db3ff60f53accdd116a7..b8beb49efd3d66cd29792807e6912772c0103c11 100644
--- a/dart/tools/testing/dart/test_runner.dart
+++ b/dart/tools/testing/dart/test_runner.dart
@@ -944,13 +944,15 @@ class ProcessQueue {
                bool printTiming,
                Function this._enqueueMoreWork,
                [bool verbose = false,
-                bool listTests = false])
+                bool listTests = false,
+                String stepName = ''])
       : _verbose = verbose,
         _listTests = listTests,
         _tests = new Queue<TestCase>(),
         _progress = new ProgressIndicator.fromName(progress,
                                                    startTime,
-                                                   printTiming),
+                                                   printTiming,
+                                                   stepName),
         _batchProcesses = new Map<String, List<BatchRunnerProcess>>(),
         _testCache = new Map<String, List<TestInformation>>() {
     if (!_enqueueMoreWork(this)) _progress.allDone();