Move dart:chrome to dart:_chrome.

tests/chrome/sample_test.dart

Index: tests/chrome/sample_test.dart
===================================================================
--- tests/chrome/sample_test.dart	(revision 27851)
+++ tests/chrome/sample_test.dart	(working copy)
@@ -1,23 +0,0 @@
-// 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 sample_test;
-import '../../pkg/unittest/lib/unittest.dart';
-import '../../pkg/unittest/lib/html_config.dart';
-import 'dart:chrome' as chrome;
-
-main() {
-  useHtmlConfiguration();
-  test('access', () {
-    var window = chrome.app.window;
-    expect(window is chrome.WindowModule, true);
-  });
-
-  test('fails from browser', () {
-    // APIs should not work in standard browser apps.
-    expect(() {
-      chrome.app.window.create('foo.html');
-    }, throws);
-  });
-}