Create an apptesting framework for dart.

third_party/dart-packages/path/BUILD.gn

Index: third_party/dart-packages/path/BUILD.gn
diff --git a/third_party/dart-packages/path/BUILD.gn b/third_party/dart-packages/path/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..ce79e928bab3a6398e25f65f6de3582f809ddbe6
--- /dev/null
+++ b/third_party/dart-packages/path/BUILD.gn
@@ -0,0 +1,21 @@
+# Copyright 2015 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//mojo/public/dart/rules.gni")
+
+dart_package("path") {
+  sources = [
+    "path/path.dart",
+    "path/src/characters.dart",
+    "path/src/context.dart",
+    "path/src/internal_style.dart",
+    "path/src/parsed_path.dart",
+    "path/src/path_exception.dart",
+    "path/src/style.dart",
+    "path/src/utils.dart",
+    "path/src/style/posix.dart",
+    "path/src/style/url.dart",
+    "path/src/style/windows.dart",
+  ]
+}