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

utils/tests/pub/update/git/do_not_update_if_unneeded_test.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 pub_tests;
 
 import 'dart:io';
 
 import '../../test_pub.dart';
-import '../../../../../pkg/unittest/unittest.dart';
+import '../../../../../pkg/unittest/lib/unittest.dart';
 
 main() {
   test("doesn't update one locked Git package's dependencies if it's not "
       "necessary", () {
     ensureGit();
 
     git('foo.git', [
       libDir('foo'),
       libPubspec("foo", "1.0.0", [{"git": "../foo-dep.git"}])
     ]).scheduleCreate();
@@ skipping 35 matching lines @@
         file('foo.dart', 'main() => "foo 2";')
       ]),
       dir('foo-dep', [
         file('foo-dep.dart', 'main() => "foo-dep";')
       ]),
     ]).scheduleValidate();
 
     run();
   });
 }