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

pkg/unittest/lib/unittest.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.
 
 /**
  * A library for writing dart unit tests.
  *
  * To import this library, use the pub package manager.
  * Create a pubspec.yaml file in your project and add
  * a dependency on unittest with the following lines:
@@ skipping 130 matching lines @@
  *           // indicate that the asynchronous callback was invoked.
  *           async.complete();
  *         });
  *       });
  *     }
  *
  */
 library unittest;
 
 import 'dart:isolate';
+import 'matcher.dart';
+export 'matcher.dart';
 
-part 'collection_matchers.dart';
 part 'config.dart';
-part 'core_matchers.dart';
-part 'description.dart';
-part 'expect.dart';
-part 'future_matchers.dart';
-part 'interfaces.dart';
-part 'map_matchers.dart';
-part 'matcher.dart';
-part 'mock.dart';
-part 'numeric_matchers.dart';
-part 'operator_matchers.dart';
-part 'string_matchers.dart';
 part 'test_case.dart';
 
 /** [Configuration] used by the unittest library. */
 Configuration _config = null;
 
 Configuration get config => _config;
 
 /**
  * Set the [Configuration] used by the unittest library. Returns any
  * previous configuration.
@@ skipping 672 matching lines @@
 }
 
 /**
  * Lazily initializes the test library if not already initialized.
  */
 ensureInitialized() {
   if (_initialized) {
     return;
   }
   _initialized = true;
+  // Hook our async guard into the matcher library.
+  wrapAsync = expectAsync1;
 
   _tests = <TestCase>[];
   _testRunner = _nextBatch;
   _uncaughtErrorMessage = null;
 
   if (_config == null) {
     _config = new Configuration();
   }
   _config.onInit();
 
@@ skipping 30 matching lines @@
 }
 
 /** Enable a test by ID. */
 void enableTest(int testId) => _setTestEnabledState(testId, true);
 
 /** Disable a test by ID. */
 void disableTest(int testId) => _setTestEnabledState(testId, false);
 
 /** Signature for a test function. */
 typedef void TestFunction();