Add ConstantExpression.evaluate.

pkg/compiler/lib/src/compile_time_constants.dart

Index: pkg/compiler/lib/src/compile_time_constants.dart
diff --git a/pkg/compiler/lib/src/compile_time_constants.dart b/pkg/compiler/lib/src/compile_time_constants.dart
index f9da31435ca5dca9a65e61feff9cbba2eccb75cd..24ea34cf314b3ab394d3f93a9a03b599d3535bb2 100644
--- a/pkg/compiler/lib/src/compile_time_constants.dart
+++ b/pkg/compiler/lib/src/compile_time_constants.dart
@@ -339,7 +339,7 @@ class CompileTimeConstantEvaluator extends Visitor<AstConstant> {
     DartType type = elements.getType(node);
     return new AstConstant(
         context, node, new ListConstantExpression(
-            new ListConstantValue(type, argumentValues),
+            constantSystem.createList(type, argumentValues),
             type,
             argumentExpressions));
   }
@@ -470,11 +470,9 @@ class CompileTimeConstantEvaluator extends Visitor<AstConstant> {
   }
 
   AstConstant makeTypeConstant(Node node, DartType elementType) {
-    DartType constantType =
-        compiler.backend.typeImplementation.computeType(compiler);
     return new AstConstant(
         context, node, new TypeConstantExpression(
-            new TypeConstantValue(elementType, constantType),
+            constantSystem.createType(compiler, elementType),
             elementType));
   }