GN: Build rules and fixes for (almost) all mojo unittest targets

mojo/public/cpp/application/tests/BUILD.gn

Index: mojo/public/cpp/application/tests/BUILD.gn
diff --git a/mojo/public/cpp/application/tests/BUILD.gn b/mojo/public/cpp/application/tests/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..4c22c1962688ada88ba6f0305bf45d63f41a2157
--- /dev/null
+++ b/mojo/public/cpp/application/tests/BUILD.gn
@@ -0,0 +1,17 @@
+# Copyright 2014 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.
+
+# GYP version: mojo/mojo_public_tests.gypi:mojo_public_application_unittests
+test("mojo_public_application_unittests") {
+  deps = [
+    "//base",
+    "//mojo/common/test:run_all_unittests",
+    "//mojo/public/cpp/application:standalone",
+    "//mojo/public/cpp/environment:standalone",
+    "//mojo/public/cpp/utility",
+    "//testing/gtest",
+  ]
+
+  sources = [ "service_registry_unittest.cc" ]
+}