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

pkg/unittest/lib/src/basematcher.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.
 
+part of matcher;
+
 /**
  * MatchState is a simple wrapper around an arbitrary object.
  * [Matcher] [matches] methods can use this to store useful
  * information upon match failures, and this information will
  * be passed to [describeMismatch]. Each [Matcher] is responsible
  * for its own use of this state, so the state created by [matches]
  * should be consistent with that expected by [describeMismatch] in
  * the same [Matcher] class, but can vary between classes. The inner
  * state, if set, will typically be a [Map] with a number of key-value
  * pairs containing relevant state information.
  */
-
-part of unittest;
-
 class MatchState {
   var state = null;
 
   MatchState([this.state]);
 }
 
 /**
  * BaseMatcher is the base class for all matchers. To implement a new
  * matcher, either add a class that implements from IMatcher or
  * a class that inherits from Matcher. Inheriting from Matcher has
@@ skipping 21 matching lines @@
    * Generates a description of the matcher failed for a particular
    * [item], by appending the description to [mismatchDescription].
    * It does not check whether the [item] fails the match, as it is
    * only called after a failed match. There may be additional info
    * about the mismatch in [matchState].
    */
   Description describeMismatch(item, Description mismatchDescription,
                                MatchState matchState, bool verbose) =>
     mismatchDescription.add('was ').addDescriptionOf(item);
 }