Teach dart_package to understand the packages/ subdirectory

third_party/dart-packages/path/path/src/path_exception.dart

Index: third_party/dart-packages/path/path/src/path_exception.dart
diff --git a/third_party/dart-packages/path/path/src/path_exception.dart b/third_party/dart-packages/path/path/src/path_exception.dart
deleted file mode 100644
index 49bd268e4d5382de9d0bc547946a19589be409d8..0000000000000000000000000000000000000000
--- a/third_party/dart-packages/path/path/src/path_exception.dart
+++ /dev/null
@@ -1,15 +0,0 @@
-// 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.
-
-library path.path_exception;
-
-/// An exception class that's thrown when a path operation is unable to be
-/// computed accurately.
-class PathException implements Exception {
-  String message;
-
-  PathException(this.message);
-
-  String toString() => "PathException: $message";
-}