Give developers a correct command line to reproduce test failures without the use of selenium.

tools/testing/dart/test_suite.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * Classes and methods for enumerating and preparing tests.
  *
  * This library includes:
  *
  * - Creating tests by listing all the Dart files in certain directories,
@@ skipping 992 matching lines @@
           // don't need to do any compilations. Thus we set "commandSet = []".
           commandSet = [];
         }
 
         var htmlPath_subtest = _createUrlPathFromFile(new Path(htmlPath));
         var fullHtmlPath = _getUriForBrowserTest(info, htmlPath_subtest,
                                                  subtestNames, subtestIndex);
 
         List<String> args = <String>[];
 
-        if (TestUtils.usesWebDriver(runtime)) {
+        if (configuration['use_browser_controller']) {
+          // This command is not actually run, it is used for reproducing
+          // the failure.
+          args = ['tools/testing/dart/launch_browser.dart',
+                  runtime,
+                  fullHtmlPath];
+          commandSet.add(new Command(TestUtils.dartTestExecutable.toString(),
+                                     args));
+        } else if (TestUtils.usesWebDriver(runtime)) {
           args = [
               dartDir.append('tools/testing/run_selenium.py').toNativePath(),
               '--browser=$runtime',
               // NOTE: This value will be overridden by the test runner
               '--timeout=${configuration['timeout']}',
               '--out=$fullHtmlPath'];
           if (runtime == 'dartium') {
             args.add('--executable=$dartiumFilename');
           }
           if (subtestIndex != 0) {
@@ skipping 922 matching lines @@
  * $pass tests are expected to pass
  * $failOk tests are expected to fail that we won't fix
  * $fail tests are expected to fail that we should fix
  * $crash tests are expected to crash that we should fix
  * $timeout tests are allowed to timeout
  * $compileErrorSkip tests are skipped on browsers due to compile-time error
 """;
     print(report);
    }
 }