Use packages dart_parser, dart_scanner, and compiler_util.

pkg/compiler/lib/src/util/util_implementation.dart

Index: pkg/compiler/lib/src/util/util_implementation.dart
diff --git a/pkg/compiler/lib/src/util/util_implementation.dart b/pkg/compiler/lib/src/util/util_implementation.dart
deleted file mode 100644
index bdb6b901c39c74b1d7d0c4577760155b4964d3d3..0000000000000000000000000000000000000000
--- a/pkg/compiler/lib/src/util/util_implementation.dart
+++ /dev/null
@@ -1,11 +0,0 @@
-// 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.
-
-library util_implementation;
-
-import 'dart:collection';
-
-import 'util.dart';
-
-part 'link_implementation.dart';