Roll Chrome into Mojo.

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_source_set") {
   # Only available on linux for now.
   assert(is_linux)
   assert(defined(invoker.cython_sources) || defined(invoker.sources))
 
   config_name = target_name + "_python_config"
@@ skipping 64 matching lines @@
   }
 }
 
 template("python_binary_module") {
   # Only available on linux for now.
   assert(is_linux)
 
   has_sources = defined(invoker.cython_sources) || defined(invoker.sources)
 
   assert(has_sources || defined(invoker.deps))
-  assert(defined(invoker.python_base_module))
+  assert(
+      !defined(invoker.python_base_module) || invoker.python_base_module != "")
 
   sources_target_name = target_name + "_cython_sources"
   shared_library_name = target_name + "_shared_library"
 
   if (is_linux) {
     shared_library_prefix = "lib"
     shared_library_suffix = ".so"
     python_module_suffix = ".so"
   }
 
@@ skipping 35 matching lines @@
     }
     if (defined(invoker.deps)) {
       deps += invoker.deps
     }
     if (defined(invoker.datadeps)) {
       datadeps = invoker.datadeps
     }
   }
 
   copy(target_name) {
-    python_base_module = invoker.python_base_module
+    if (defined(invoker.python_base_module)) {
+      python_base_module = invoker.python_base_module
+      output = "$root_out_dir/python/$python_base_module/${target_name}${python_module_suffix}"
+    } else {
+      output = "$root_out_dir/python/${target_name}${python_module_suffix}"
+    }
+
     sources = [
       "$root_out_dir/${shared_library_prefix}${shared_library_name}${shared_library_suffix}",
     ]
     outputs = [
-      "$root_out_dir/python/$python_base_module/${target_name}${python_module_suffix}",
+      output,
     ]
     deps = [
       ":$shared_library_name",
     ]
   }
 }