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

utils/tests/pub/install/git/require_pubspec_name_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('requires the dependency to have a pubspec with a name field', () {
     ensureGit();
 
     git('foo.git', [
       libDir('foo'),
       pubspec({})
     ]).scheduleCreate();
 
     appDir([{"git": "../foo.git"}]).scheduleCreate();
 
     // TODO(nweiz): clean up this RegExp when either issue 4706 or 4707 is
     // fixed.
     schedulePub(args: ['install'],
         error: const RegExp(r'^Package "foo"' "'" 's pubspec.yaml file is '
             r'missing the required "name" field \(e\.g\. "name: foo"\)\.'),
         exitCode: 1);
 
     run();
   });
 }