Address comments directly in master, adjust for new sdk html fields.

lib/testing/render_test.dart

 // Copyright (c) 2013, 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.
 
 /**
  * This is a helper for run.sh. We try to run all of the Dart code in one
  * instance of the Dart VM to reduce warm-up time.
  */
 library web_ui.testing.render_test;
 
 import 'dart:io';
 import 'dart:math' show min;
 import 'package:pathos/path.dart' as path;
 import 'package:unittest/unittest.dart';
 import 'package:web_ui/dwc.dart' as dwc;
 
 void renderTests(String baseDir, String inputDir, String expectedDir,
-    String outDir, [List<String> args, String script, String pattern,
-    bool deleteDir = true]) {
-  if (args == null) args = new Options().arguments;
+    String outDir, {List<String> arguments, String script, String pattern,
+    bool deleteDir: true}) {
+  if (arguments == null) arguments = new Options().arguments;
   if (script == null) script = new Options().script;
 
   var filePattern = new RegExp(pattern != null ? pattern : '.');
 
   var scriptDir = path.absolute(path.dirname(script));
   baseDir = path.join(scriptDir, baseDir);
   inputDir = path.join(scriptDir, inputDir);
   expectedDir = path.join(scriptDir, expectedDir);
   outDir = path.join(scriptDir, outDir);
 
   var paths = new Directory(inputDir).listSync()
       .where((f) => f is File).map((f) => f.path)
       .where((p) => p.endsWith('_test.html') && filePattern.hasMatch(p));
 
   // First clear the output folder. Otherwise we can miss bugs when we fail to
   // generate a file.
   var dir = new Directory(outDir);
   if (dir.existsSync() && deleteDir) {
     print('Cleaning old output for ${path.normalize(outDir)}');
     dir.deleteSync(recursive: true);
   }
   dir.createSync();
 
-  args.addAll(['-o', outDir, '--basedir', baseDir]);
+  arguments.addAll(['-o', outDir, '--basedir', baseDir]);
   for (var filePath in paths) {
     var filename = path.basename(filePath);
     test('compile $filename', () {
-      var testArgs = args.toList();
+      var testArgs = arguments.toList();
       testArgs.add(filePath);
       expect(dwc.run(testArgs, printTime: false).then((res) {
         expect(res.messages.length, 0, reason: res.messages.join('\n'));
       }), completes);
     });
   }
 
   if (!paths.isEmpty) {
     var filenames = paths.map(path.basename).toList();
     // Sort files to match the order in which run.sh runs diff.
@@ skipping 27 matching lines @@
         var outPath = path.join(outDir, '$filename.txt');
         var expectedPath = path.join(expectedDir, '$filename.txt');
         new File(outPath).writeAsStringSync(output);
         var expected = new File(expectedPath).readAsStringSync();
         expect(output, expected,
           reason: 'unexpected output for <$filename>');
       });
     }
   }
 }