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..ee1f7c0e9ca60a271a9b17de6056c08e60f7e612 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(
+              'jsonOnly',

[ricow1, 2015/01/13 08:03:01]

we don't store these using camel case, and to be specific, I would call this:
--report-in-json

[kevmoo, 2015/01/13 19:27:35]

Done.

+              'When doing list, output result summary in json only.',
+              ['--json-only'],
+              [],
+              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['jsonOnly']) {
+      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') {