Restructure pkg/unittest and pkg/webdriver to follow the pub conventions.

tests/html/shadow_dom_test.dart

 // Copyright (c) 2011, 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('ShadowDOMTest');
-#import('../../pkg/unittest/unittest.dart');
-#import('../../pkg/unittest/html_config.dart');
-#import('dart:html');
+library ShadowDOMTest;
+import '../../pkg/unittest/lib/unittest.dart';
+import '../../pkg/unittest/lib/html_config.dart';
+import 'dart:html';
 
 main() {
   useHtmlConfiguration();
 
   group('ShadowDOM tests', () {
 
     var div1, div2, shadowRoot, paragraph1, paragraph2;
 
     setUp(() {
       paragraph1 = new ParagraphElement();
@@ skipping 24 matching lines @@
     // TODO(samhop): test that <content> and <content select="foo"> and
     // <shadow>
     // work properly. This is blocked on having a good way to do browser
     // rendering tests.
 
     test('Querying in shadowed fragment respects the shadow boundary.', () {
       expect(shadowRoot.queryAll('.foo'), equals([paragraph1]));
     });
   });
 }