Provide mechanism to close immediately to Dart bindings

mojo/public/tools/bindings/generators/dart_templates/interface_definition.tmpl

Index: mojo/public/tools/bindings/generators/dart_templates/interface_definition.tmpl
diff --git a/mojo/public/tools/bindings/generators/dart_templates/interface_definition.tmpl b/mojo/public/tools/bindings/generators/dart_templates/interface_definition.tmpl
index 30463b2b6a096c625bf883ae52b29538ece8078f..99e2ab35ac193219311dc07d2fcc41c4232e7816 100644
--- a/mojo/public/tools/bindings/generators/dart_templates/interface_definition.tmpl
+++ b/mojo/public/tools/bindings/generators/dart_templates/interface_definition.tmpl
@@ -158,7 +158,7 @@ class {{interface|name}}Proxy implements bindings.ProxyBase {
       core.MojoMessagePipeEndpoint endpoint) =>
       new {{interface|name}}Proxy.fromEndpoint(endpoint);
 
-  Future close({bool nodefer: false}) => impl.close(nodefer: nodefer);
+  Future close({bool immediate: false}) => impl.close(immediate: immediate);
 
   String toString() {
     return "{{interface|name}}Proxy($impl)";