Add getter for lineMode and echoMode for Stdin.

tests/standalone/io/stdin_sync_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.
 
 import "dart:convert";
 import "dart:io";
 
 import "package:path/path.dart";
+import "package:expect/expect.dart";
 
 void testReadByte() {
   void test(String line, List<String> expected) {
     var script = Platform.script.resolve("stdin_sync_script.dart").toFilePath();
     Process.start(Platform.executable,
                   ["--checked", script]..addAll(
                       expected.map(JSON.encode))).then((process) {
       process.stdin.write(line);
       process.stdin.close();
       process.stderr
@@ skipping 18 matching lines @@
   test("hej\u0187", ['hej\u0187']);
 
   test("hej\rhej\nhej\r", ['hej\rhej', 'hej\r']);
 
   test("hej\r\r\nhej\r\nhej\r", ['hej\r', 'hej', 'hej\r']);
 
   test("hej", ['hej']);
 }
 
 void testEchoMode() {
+  stdin.echoMode = true;
+  Expect.isTrue(stdin.echoMode);
   stdin.echoMode = false;
+  Expect.isFalse(stdin.echoMode);
   var line;
   while ((line = stdin.readLineSync()) != null) {
     print("You typed: $line");
   }
 }
 
 void testLineMode() {
+  stdin.lineMode = true;
+  Expect.isTrue(stdin.lineMode);
   stdin.lineMode = false;
+  Expect.isFalse(stdin.lineMode);
   var char;
   while ((char = stdin.readByteSync()) != -1) {
     print("You typed: $char");
   }
 }
 
 
 void main() {
   testReadByte();
 
   // testEchoMode and testLineMode is an developer-interactive test, thus not
   // enabled.
   //testEchoMode();
   //testLineMode();
 }