Dart: Reorganize files

mojo/dart/observatory_test/BUILD.gn

Index: mojo/dart/observatory_test/BUILD.gn
diff --git a/mojo/dart/observatory_test/BUILD.gn b/mojo/dart/observatory_test/BUILD.gn
deleted file mode 100644
index b845c9fbfcb1a3531fbb1c035fc8196ff54844a8..0000000000000000000000000000000000000000
--- a/mojo/dart/observatory_test/BUILD.gn
+++ /dev/null
@@ -1,18 +0,0 @@
-# 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_pkg("observatory_test") {
-  apps = [ [
-        "dart_observatory_test",
-        "lib/main.dart",
-      ] ]
-  sources = [
-    "pubspec.yaml",
-  ]
-  deps = [
-    "//mojo/public/dart",
-  ]
-}