pkg/mock: restructure library layout

pkg/mock/lib/src/util.dart

+// 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 mock.util;
+
+import 'package:matcher/matcher.dart';
+
+/** Utility function for optionally qualified method names */
+String qualifiedName(owner, String method) {
+  if (owner == null || identical(owner, anything)) {
+    return method;
+  } else if (owner is Matcher) {
+    Description d = new StringDescription();
+    d.addDescriptionOf(owner);
+    d.add('.');
+    d.add(method);
+    return d.toString();
+  } else {
+    return '$owner.$method';
+  }
+}
+
+/** Sentinel value for representing no argument. */
+class _Sentinel {
+  const _Sentinel();
+}
+const NO_ARG = const _Sentinel();