All strong mode cleaning of dart2js.

pkg/compiler/lib/src/universe/class_set.dart

 // Copyright (c) 2015, 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 dart2js.world.class_set;
 
 import 'dart:collection' show IterableBase;
 
 import '../elements/elements.dart' show ClassElement;
 import '../elements/entities.dart' show ClassEntity;
@@ skipping 325 matching lines @@
     if (subclass != null) {
       return subclass.getLubOfInstantiatedSubclasses();
     }
     return cls;
   }
 
   void printOn(StringBuffer sb, String indentation,
       {bool instantiatedOnly: false,
       bool sorted: true,
       ClassElement withRespectTo}) {
-    bool isRelatedTo(ClassElement subclass) {
+    bool isRelatedTo(ClassEntity _subclass) {
+      ClassElement subclass = _subclass;
       return subclass == withRespectTo ||
           subclass.implementsInterface(withRespectTo);
     }
 
     sb.write(indentation);
     if (cls.isAbstract) {
       sb.write('abstract ');
     }
     sb.write('class ${cls.name}:');
     if (isDirectlyInstantiated) {
@@ skipping 561 matching lines @@
   STOP,
 
   /// Iteration skips the subclasses of the current class.
   SKIP_SUBCLASSES,
 }
 
 /// Visiting function used for the `forEachX` functions of [ClassHierarchyNode]
 /// and [ClassSet]. The return value controls the continued iteration. If `null`
 /// is returned, iteration continues to the end.
 typedef IterationStep ForEachFunction(ClassEntity cls);