Tighten up a bunch of types in test.dart.

tools/testing/dart/record_and_replay.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.
 
 library record_and_replay;
 
 import 'dart:io';
 import 'dart:convert';
 
 import 'path.dart';
@@ skipping 16 matching lines @@
  *       'stderr' : '...',
  *       'duration' : 1.5,
  *       'did_timeout' : false,
  *     },
  *   },
  *   ....
  * ]
  */
 
 List<String> makePathsRelativeToDart(String cwd, List<String> arguments) {
-  var relativeArguments = [];
+  var relativeArguments = <String>[];
   for (var rawArgument in arguments) {
     if (rawArgument.startsWith(cwd)) {
       var relative = new Path(rawArgument).relativeTo(new Path(cwd));
       relativeArguments.add(relative.toNativePath());
     } else {
       relativeArguments.add(rawArgument);
     }
   }
   return relativeArguments;
 }
 
 class TestCaseRecorder {
   Path _outputPath;
   List<Map> _recordedCommandInvocations = [];
-  var _cwd;
+  String _cwd;
 
   TestCaseRecorder(this._outputPath) {
     _cwd = Directory.current.path;
   }
 
   void nextCommand(ProcessCommand command, int timeout) {
     // Convert arguments from absolute to relative paths (relative to the dart
     // directory) because the absolute path on the machine where we record
     // may be different from the absolute path on the machine where we execute
     // the commands.
@@ skipping 13 matching lines @@
   void finish() {
     var file = new File(_outputPath.toNativePath());
     var jsonString = JSON.encode(_recordedCommandInvocations);
     file.writeAsStringSync(jsonString);
     print("TestCaseRecorder: written all TestCases to ${_outputPath}");
   }
 }
 
 class TestCaseOutputArchive {
   Map<String, Map> _commandOutputRecordings;
-  var _cwd;
+  String _cwd;
 
   TestCaseOutputArchive() {
     _cwd = Directory.current.path;
   }
 
   void loadFromPath(Path recordingPath) {
     var file = new File(recordingPath.toNativePath());
     var commandRecordings = JSON.decode(file.readAsStringSync());
     _commandOutputRecordings = {};
     for (var commandRecording in commandRecordings) {
@@ skipping 29 matching lines @@
         UTF8.encode(command_output['stderr']),
         duration,
         false);
     return commandOutput;
   }
 
   String _indexKey(String executable, String arguments) {
     return "${executable}__$arguments";
   }
 }