Outputing comma-separated report with percentages

tools/testing/dart/test_options.dart

Index: tools/testing/dart/test_options.dart
diff --git a/tools/testing/dart/test_options.dart b/tools/testing/dart/test_options.dart
index 940c5cc8cf2223457787b3db2c49ea4eaf485ec8..c004ee6ccc945a12da26802eba84acb1663c7974 100644
--- a/tools/testing/dart/test_options.dart
+++ b/tools/testing/dart/test_options.dart
@@ -222,6 +222,13 @@ class TestOptionsParser {
               false,
               type: 'bool'),
           new _TestOptionSpecification(
+              'report_in_json',
+              'When doing list, output result summary in json only.',
+              ['--report-in-json'],
+              [],
+              false,
+              type: 'bool'),
+          new _TestOptionSpecification(
               'time',
               'Print timing information after running tests',
               ['--time'],
@@ -681,6 +688,11 @@ Note: currently only implemented for dart2js.''',
       configuration['mode'] = 'debug,release';
     }
 
+    if (configuration['report_in_json']) {
+      configuration['list'] = true;
+      configuration['report'] = true;
+    }
+
     // Use verbose progress indication for verbose output unless buildbot
     // progress indication is requested.
     if (configuration['verbose'] && configuration['progress'] != 'buildbot') {