Finish strong mode cleaning of dart2js.

pkg/compiler/lib/src/js_emitter/parameter_stub_generator.dart

Index: pkg/compiler/lib/src/js_emitter/parameter_stub_generator.dart
diff --git a/pkg/compiler/lib/src/js_emitter/parameter_stub_generator.dart b/pkg/compiler/lib/src/js_emitter/parameter_stub_generator.dart
index 637d5813349d9f05c4fc020d9bcb4ecf864b45fa..a018b6f5b3387e838537d6cede33166031361018 100644
--- a/pkg/compiler/lib/src/js_emitter/parameter_stub_generator.dart
+++ b/pkg/compiler/lib/src/js_emitter/parameter_stub_generator.dart
@@ -121,7 +121,8 @@ class ParameterStubGenerator {
     // Includes extra receiver argument when using interceptor convention
     int indexOfLastOptionalArgumentInParameters = optionalParameterStart - 1;
 
-    parameters.orderedForEachParameter((ParameterElement element) {
+    parameters.orderedForEachParameter((_element) {
+      ParameterElement element = _element;
       String jsName = _namer.safeVariableName(element.name);
       assert(jsName != receiverArgumentName);
       if (count < optionalParameterStart) {