Roll Chrome into Mojo.

third_party/cython/rules.gni

Index: third_party/cython/rules.gni
diff --git a/third_party/cython/rules.gni b/third_party/cython/rules.gni
index 5cfea1ab45aa66210ef8e1a53eee927f5ac0bb90..04a9953e1df16b37b2f2901e1d829609b1b7f29c 100644
--- a/third_party/cython/rules.gni
+++ b/third_party/cython/rules.gni
@@ -82,7 +82,8 @@ template("python_binary_module") {
   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"
@@ -138,12 +139,18 @@ template("python_binary_module") {
   }
 
   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",