Break up common_custom_types.mojom.

mojo/common/version.mojom

Index: mojo/common/version.mojom
diff --git a/mojo/common/version.mojom b/mojo/common/version.mojom
new file mode 100644
index 0000000000000000000000000000000000000000..6ddf6e6b8cd0acd03fecb863db46a150e0637d53
--- /dev/null
+++ b/mojo/common/version.mojom
@@ -0,0 +1,10 @@
+// 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.
+
+module mojo.common.mojom;
+
+// Corresponds to |base::Version| in base/version.h
+struct Version {
+  array<uint32> components;
+};