Re-apply "Remove unittest and matcher from the repo."

pkg/matcher/lib/src/prints_matcher.dart

Index: pkg/matcher/lib/src/prints_matcher.dart
diff --git a/pkg/matcher/lib/src/prints_matcher.dart b/pkg/matcher/lib/src/prints_matcher.dart
deleted file mode 100644
index 8faa8956abe65a7d42107ec2e467c392f0f651e9..0000000000000000000000000000000000000000
--- a/pkg/matcher/lib/src/prints_matcher.dart
+++ /dev/null
@@ -1,72 +0,0 @@
-// Copyright (c) 2014, 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 matcher.prints_matcher;
-
-import 'dart:async';
-
-import 'description.dart';
-import 'expect.dart';
-import 'interfaces.dart';
-import 'future_matchers.dart';
-import 'util.dart';
-
-/// Matches a [Function] that prints text that matches [matcher].
-///
-/// [matcher] may be a String or a [Matcher].
-///
-/// If the function this runs against returns a [Future], all text printed by
-/// the function (using [Zone] scoping) until that Future completes is matched.
-///
-/// This only tracks text printed using the [print] function.
-Matcher prints(matcher) => new _Prints(wrapMatcher(matcher));
-
-class _Prints extends Matcher {
-  final Matcher _matcher;
-
-  _Prints(this._matcher);
-
-  bool matches(item, Map matchState) {
-    if (item is! Function) return false;
-
-    var buffer = new StringBuffer();
-    var result = runZoned(item, zoneSpecification:
-        new ZoneSpecification(print: (_, __, ____, line) {
-      buffer.writeln(line);
-    }));
-
-    if (result is! Future) {
-      var actual = buffer.toString();
-      matchState['prints.actual'] = actual;
-      return _matcher.matches(actual, matchState);
-    }
-
-    return completes.matches(result.then(wrapAsync((_) {
-      expect(buffer.toString(), _matcher);
-    }, 'prints')), matchState);
-  }
-
-  Description describe(Description description) =>
-      description.add('prints ').addDescriptionOf(_matcher);
-
-  Description describeMismatch(item, Description description, Map matchState,
-      bool verbose) {
-    var actual = matchState.remove('prints.actual');
-    if (actual == null) return description;
-    if (actual.isEmpty) return description.add("printed nothing.");
-
-    description.add('printed ').addDescriptionOf(actual);
-
-    // Create a new description for the matcher because at least
-    // [_StringEqualsMatcher] replaces the previous contents of the description.
-    var innerMismatch = _matcher.describeMismatch(
-        actual, new StringDescription(), matchState, verbose).toString();
-
-    if (innerMismatch.isNotEmpty) {
-      description.add('\n   Which: ').add(innerMismatch.toString());
-    }
-
-    return description;
-  }
-}