Add catalog unittests

mojo/services/catalog/entry.cc

Index: mojo/services/catalog/entry.cc
diff --git a/mojo/services/catalog/entry.cc b/mojo/services/catalog/entry.cc
new file mode 100644
index 0000000000000000000000000000000000000000..9d6f40f449b2fb4d6a1098c90355a2330b17d996
--- /dev/null
+++ b/mojo/services/catalog/entry.cc
@@ -0,0 +1,13 @@
+// Copyright 2016 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.
+
+#include "mojo/services/catalog/entry.h"
+
+namespace catalog {
+
+Entry::Entry() {}
+Entry::Entry(const Entry& other) = default;
+Entry::~Entry() {}
+
+}  // catalog