Roll Chrome into Mojo.

mojo/public/python/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("//third_party/cython/rules.gni")
 
 group("python") {
   deps = [
     ":bindings",
     ":mojo_system",
     ":mojo_system_impl",
   ]
 }
 
 # GYP version: mojo.gyp:mojo_python_system
 python_binary_module("mojo_system") {
-  python_base_module = ""
   configs = [ "../build/config:mojo_sdk" ]
   deps = [
     ":system_embedded",
   ]
 }
 
 python_binary_source_set("system_embedded") {
   cython_sources = [
     "c_async_waiter.pxd",
     "c_core.pxd",
     "c_export.pxd",
     "c_thunks.pxd",
     "mojo_system.pyx",
   ]
   configs = [ "../build/config:mojo_sdk" ]
   deps = [
     "../c/system",
     "../cpp/bindings:callback",
     "../cpp/system",
     "../cpp/utility",
     "../platform/native:system",
   ]
 }
 
 python_binary_module("mojo_system_impl") {
-  python_base_module = ""
   cython_sources = [
     "c_environment.pxd",
     "c_export.pxd",
     "c_thunks.pxd",
     "mojo_system_impl.pyx",
   ]
   sources = [
     "src/python_system_helper.cc",
     "src/python_system_helper.h",
   ]
@@ skipping 35 matching lines @@
     "mojo_bindings/reflection.py",
     "mojo_bindings/serialization.py",
   ]
   outputs = [
     "$root_out_dir/python/mojo_bindings/{{source_file_part}}",
   ]
   deps = [
     ":mojo_system",
   ]
 }