Revert "Use relative URIs for core library part-of statements."

sdk/lib/math/point.dart

Index: sdk/lib/math/point.dart
diff --git a/sdk/lib/math/point.dart b/sdk/lib/math/point.dart
index f6bc26adf20de7efece88ccc66c2b83e51363891..34c8b5066604e4362c980499e60e327a6e55efe9 100644
--- a/sdk/lib/math/point.dart
+++ b/sdk/lib/math/point.dart
@@ -1,8 +1,7 @@
 // Copyright (c) 2013, 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 "math.dart";
+part of dart.math;
 
 /**
  * A utility class for representing two-dimensional positions.