Changes to make compiler_util a standalone package.

pkg/compiler_util/lib/src/link_implementation.dart

Index: pkg/compiler_util/lib/src/link_implementation.dart
diff --git a/pkg/compiler_util/lib/src/link_implementation.dart b/pkg/compiler_util/lib/src/link_implementation.dart
index 186bfffd2106a8d14e138dfab87269315b3d64a6..40027712adb6d70a2d78c6dea8c1bea10deb290c 100644
--- a/pkg/compiler_util/lib/src/link_implementation.dart
+++ b/pkg/compiler_util/lib/src/link_implementation.dart
@@ -2,7 +2,14 @@
 // 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 util_implementation;
+library compiler_util.link_implementation;
+
+import 'dart:collection' show
+    IterableBase;
+
+import '../link.dart' show
+    Link,
+    LinkBuilder;
 
 class LinkIterator<T> implements Iterator<T> {
   T _current;