Use Entity instead of Element in ConstantValue

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 d99734e4eca7876d7b6253a5e557a6f9e5467cf7..13cb0a01d332fdfeecdd8004320c301c7a5919d8 100644
--- a/pkg/compiler/lib/src/compile_time_constants.dart
+++ b/pkg/compiler/lib/src/compile_time_constants.dart
@@ -637,13 +637,13 @@ class CompileTimeConstantEvaluator extends Visitor<AstConstant> {
     if (send.isPropertyAccess) {
       AstConstant result;
       if (Elements.isStaticOrTopLevelFunction(element)) {
-        FunctionElement function = element;
+        MethodElement function = element;
         function.computeType(resolution);
         result = new AstConstant(
             context,
             send,
             new FunctionConstantExpression(function),
-            new FunctionConstantValue(function));
+            new FunctionConstantValue(function, function.type));
       } else if (Elements.isStaticOrTopLevelField(element)) {
         ConstantExpression elementExpression;
         if (element.isConst) {