Break up common_custom_types.mojom.

mojo/common/BUILD.gn

 # 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.
 
 import("//mojo/public/tools/bindings/mojom.gni")
 import("//testing/test.gni")
 
 group("common") {
   public_deps = [
     ":common_base",
     ":common_custom_types",
   ]
 }
 
 mojom("common_custom_types") {
   sources = [
-    "common_custom_types.mojom",
+    "file.mojom",
+    "file_path.mojom",
+    "string16.mojom",
+    "time.mojom",
+    "unguessable_token.mojom",
+    "values.mojom",
+    "version.mojom",
   ]
 }
 
 component("common_base") {
   output_name = "mojo_common_lib"
 
   sources = [
     "common_type_converters.cc",
     "common_type_converters.h",
     "data_pipe_drainer.cc",
@@ skipping 62 matching lines @@
   sources = [
     "common_custom_types_struct_traits.cc",
     "common_custom_types_struct_traits.h",
   ]
   deps = [
     ":common_custom_types_shared_cpp_sources",
     "//base:base",
     "//mojo/public/cpp/system",
   ]
 }