Add browser path options to testing scripts.

tools/testing/dart/utils.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.
 
 library utils;
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:math' show min;
 import 'dart:convert';
@@ skipping 107 matching lines @@
   return UTF8.encode(string);
 }
 
 // TODO(kustermann,ricow): As soon we have a debug log we should log
 // invalid utf8-encoded input to the log.
 // Currently invalid bytes will be replaced by a replacement character.
 String decodeUtf8(List<int> bytes) {
   return UTF8.decode(bytes, allowMalformed: true);
 }
 
+// This is only used for selenium support for Dartium.  Remove the class
+// when this support goes away.
 class Locations {
   static String getDartiumLocation(Map globalConfiguration) {
     var dartium = globalConfiguration['dartium'];
     if (dartium != null && dartium != '') {
       return dartium;
     }
     if (Platform.operatingSystem == 'macos') {
       return new Path('client/tests/dartium/Chromium.app/Contents/'
           'MacOS/Chromium').toNativePath();
     }
@@ skipping 22 matching lines @@
 
 class UniqueObject {
   static int _nextId = 1;
   final int _hashCode;
 
   int get hashCode => _hashCode;
   operator==(other) => other is UniqueObject && _hashCode == other._hashCode;
 
   UniqueObject() : _hashCode = ++_nextId;
 }