Add ConstantExpression.evaluate.

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

 // Copyright (c) 2013, 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.
 
 part of js_backend;
 
 /**
  * Support for Custom Elements.
  *
  * The support for custom elements the compiler builds a table that maps the
@@ skipping 160 matching lines @@
             constant, compiler.globalDependencies);
         backend.constants.addCompileTimeConstantForEmission(constant);
       }
     }
     activeClasses.addAll(newActiveClasses);
     instantiatedClasses.removeAll(newActiveClasses);
   }
 
   TypeConstantValue makeTypeConstant(ClassElement element) {
     DartType elementType = element.rawType;
-    DartType constantType = backend.typeImplementation.rawType;
-    return new TypeConstantValue(elementType, constantType);
+    return backend.constantSystem.createType(compiler, elementType);
   }
 
   List<Element> computeEscapingConstructors(ClassElement classElement) {
     List<Element> result = <Element>[];
     // Only classes that extend native classes have constructors in the table.
     // We could refine this to classes that extend Element, but that would break
     // the tests and there is no sane reason to subclass other native classes.
     if (classElement.isNative) return result;
 
     selectGenerativeConstructors(ClassElement enclosing, Element member) {
       if (member.isGenerativeConstructor) {
         // Ignore constructors that cannot be called with zero arguments.
         FunctionElement constructor = member;
         constructor.computeSignature(compiler);
         FunctionSignature parameters = constructor.functionSignature;
         if (parameters.requiredParameterCount == 0) {
           result.add(member);
         }
       }
     }
     classElement.forEachMember(selectGenerativeConstructors,
         includeBackendMembers: false,
         includeSuperAndInjectedMembers: false);
     return result;
   }
 }