Use entities in BackendClasses

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

 // Copyright (c) 2012, 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.constant_system.js;
 
 import '../compiler.dart' show Compiler;
 import '../constant_system_dart.dart';
 import '../constants/constant_system.dart';
 import '../constants/values.dart';
@@ skipping 302 matching lines @@
   NullConstantValue createNull() => new NullConstantValue();
 
   @override
   ListConstantValue createList(
       ResolutionInterfaceType type, List<ConstantValue> values) {
     return new ListConstantValue(type, values);
   }
 
   @override
   ConstantValue createType(Compiler compiler, ResolutionDartType type) {
-    ResolutionInterfaceType instanceType = compiler
-        .backend.backendClasses.typeImplementation
-        .computeType(compiler.resolution);
+    ResolutionInterfaceType instanceType =
+        compiler.backend.backendClasses.typeType;
     return new TypeConstantValue(type, instanceType);
   }
 
   // Integer checks report true for -0.0, INFINITY, and -INFINITY.  At
   // runtime an 'X is int' check is implemented as:
   //
   // typeof(X) === "number" && Math.floor(X) === X
   //
   // We consistently match that runtime semantics at compile time as well.
   bool isInt(ConstantValue constant) {
@@ skipping 122 matching lines @@
       result.add(keyList);
     } else {
       // Add the keys individually to avoid generating an unused list constant
       // for the keys.
       result.addAll(keys);
     }
     result.addAll(values);
     return result;
   }
 }