Update unittest to new package layout.

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('../../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();
       paragraph2 = new ParagraphElement();
       [paragraph1, paragraph2].forEach((p) { p.classes.add('foo');});
       div1 = new DivElement();
       div2 = new DivElement();
       div1.classes.add('foo');
       shadowRoot = new ShadowRoot(div2);
       shadowRoot.nodes.add(paragraph1);
       // No constructor for ContentElement exists yet.
       // See http://code.google.com/p/dart/issues/detail?id=3870.
       shadowRoot.nodes.add(new Element.tag('content'));
       div2.nodes.add(paragraph2);
       document.body.nodes.add(div1);
       document.body.nodes.add(div2);
     });
 
     test("Shadowed nodes aren't visible to queries from outside ShadowDOM", () {
       expect(queryAll('.foo'), equals([div1, paragraph2]));
     });
 
     test('Parent node of a shadow root must be null.', () {
       expect(shadowRoot.parent, isNull);
     });
 
-    
+
     // 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]));
-    }); 
+    });
   });
 }