Fix a type-o in browser_manager.

lib/src/runner/browser/browser_manager.dart

 // Copyright (c) 2015, 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 test.runner.browser.browser_manager;
 
 import 'dart:async';
 import 'dart:convert';
 
 import 'package:async/async.dart';
@@ skipping 236 matching lines @@
         await _environment,
         _deserializeEntries(suiteChannel, mapper, response["entries"]),
         platform: _platform,
         metadata: metadata,
         path: path,
         onClose: () => closeIframe());
   }
 
   /// Deserializes [entries] into concrete [SuiteEntry] subclasses.
   Iterable<SuiteEntry> _deserializeEntries(MultiChannel suiteChannel,
-      Mapper mapper, List<Map> entries) {
+      StackTraceMapper mapper, List<Map> entries) {
     return entries.map((entry) {
       var metadata = new Metadata.deserialize(entry['metadata']);
       if (entry['type'] == 'group') {
         return new Group(
             entry['name'],
             metadata,
             _deserializeEntries(suiteChannel, mapper, entry['entries']));
       } else {
         var testChannel = suiteChannel.virtualChannel(entry['channel']);
         return new IframeTest(entry['name'], metadata, testChannel,
@@ skipping 43 matching lines @@
 
   final Uri observatoryUrl;
 
   final Uri remoteDebuggerUrl;
 
   _BrowserEnvironment(this._manager, this.observatoryUrl,
       this.remoteDebuggerUrl);
 
   CancelableFuture displayPause() => _manager._displayPause();
 }