Add ElementCodegenWorldBuilder

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

 // Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library js_backend.backend.codegen_listener;
 
 import '../common/names.dart' show Identifiers;
 import '../common_elements.dart' show CommonElements, ElementEnvironment;
 import '../constants/values.dart';
 import '../elements/elements.dart';
@@ skipping 87 matching lines @@
       // The JavaScript backend of [Isolate.spawnUri] uses the same internal
       // implementation as [Isolate.spawn], and fails if it cannot look main up
       // by name.
       impactBuilder.registerStaticUse(new StaticUse.staticTearOff(mainMethod));
     }
     _impacts.isolateSupport.registerImpact(impactBuilder, _elementEnvironment);
     return impactBuilder;
   }
 
   /// Computes the [WorldImpact] of calling [mainMethod] as the entry point.
-  WorldImpact _computeMainImpact(MethodElement mainMethod) {
+  WorldImpact _computeMainImpact(FunctionEntity mainMethod) {
     WorldImpactBuilderImpl mainImpact = new WorldImpactBuilderImpl();
-    if (mainMethod.parameters.isNotEmpty) {
+    CallStructure callStructure = mainMethod.parameterStructure.callStructure;
+    if (callStructure.argumentCount > 0) {
       _impacts.mainWithArguments
           .registerImpact(mainImpact, _elementEnvironment);
       mainImpact.registerStaticUse(
-          new StaticUse.staticInvoke(mainMethod, CallStructure.TWO_ARGS));
+          new StaticUse.staticInvoke(mainMethod, callStructure));
       // If the main method takes arguments, this compilation could be the
       // target of Isolate.spawnUri. Strictly speaking, that can happen also if
       // main takes no arguments, but in this case the spawned isolate can't
       // communicate with the spawning isolate.
       mainImpact.addImpact(_enableIsolateSupport(mainMethod));
     }
     mainImpact.registerStaticUse(
         new StaticUse.staticInvoke(mainMethod, CallStructure.NO_ARGS));
     return mainImpact;
   }
@@ skipping 209 matching lines @@
   WorldImpact registerInstantiatedClass(ClassEntity cls) {
     return _processClass(cls);
   }
 
   @override
   void logSummary(void log(String message)) {
     _lookupMapAnalysis.logSummary(log);
     _nativeEnqueuer.logSummary(log);
   }
 }