Add ElementCodegenWorldBuilder

pkg/compiler/lib/src/js_backend/resolution_listener.dart

Index: pkg/compiler/lib/src/js_backend/resolution_listener.dart
diff --git a/pkg/compiler/lib/src/js_backend/resolution_listener.dart b/pkg/compiler/lib/src/js_backend/resolution_listener.dart
index 09eb2ce69b8cbbf87a3037213b06b71856f743c5..2abec233d538bad87134e0bb770bc26cebf6f818 100644
--- a/pkg/compiler/lib/src/js_backend/resolution_listener.dart
+++ b/pkg/compiler/lib/src/js_backend/resolution_listener.dart
@@ -153,11 +153,7 @@ class ResolutionEnqueuerListener extends EnqueuerListener {
   /// Computes the [WorldImpact] of calling [mainMethod] as the entry point.
   WorldImpact _computeMainImpact(FunctionEntity mainMethod) {
     WorldImpactBuilderImpl mainImpact = new WorldImpactBuilderImpl();
-    ParameterStructure parameterStructure = mainMethod.parameterStructure;
-    CallStructure callStructure = new CallStructure(
-        parameterStructure.positionalParameters +
-            parameterStructure.namedParameters.length,
-        parameterStructure.namedParameters);
+    CallStructure callStructure = mainMethod.parameterStructure.callStructure;
     if (callStructure.argumentCount > 0) {
       _impacts.mainWithArguments
           .registerImpact(mainImpact, _elementEnvironment);