mojo: Add a runloop utility in python

third_party/cython/rules.gni

 # 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.
 
 template("python_binary_module") {
   # Only available on linux for now.
   assert(is_linux)
   assert(defined(invoker.sources))
   assert(defined(invoker.python_base_module))
 
@@ skipping 54 matching lines @@
     deps = [
       ":$generator_target_name",
     ]
     if (defined(invoker.deps)) {
       deps += invoker.deps
     }
     if (defined(invoker.datadeps)) {
       datadeps = invoker.datadeps
     }
     sources = [ cython_output ]
+    if (defined(invoker.additional_sources)) {
+      sources += invoker.additional_sources
+    }
     configs += [ ":$config_name" ]
   }
 
   copy(target_name) {
     python_base_module = invoker.python_base_module
     sources = [
       "$root_out_dir/${shared_library_prefix}${shared_library_name}${shared_library_suffix}"
     ]
     outputs = [
       "$root_out_dir/python/$python_base_module/${target_name}${python_module_suffix}"
     ]
     deps = [
       ":$shared_library_name"
     ]
   }
 }