Use Entity instead of Element in ConstantValue

pkg/compiler/lib/src/kernel/kernel_visitor.dart

 // Copyright (c) 2016, 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.md file.
 
 import 'package:kernel/ast.dart' as ir;
 import 'package:kernel/frontend/accessors.dart'
     show
         Accessor,
         IndexAccessor,
         NullAwarePropertyAccessor,
@@ skipping 2231 matching lines @@
       MethodElement setter, NodeList parameters, Node body, _) {
     return buildIrFunction(ir.ProcedureKind.Setter, setter, body);
   }
 
   @override
   ir.Expression handleStaticSetterGet(Send node, FunctionElement setter, _) {
     return buildStaticAccessor(null, setter).buildSimpleRead();
   }
 
   @override
-  ir.Expression handleStaticSetterInvoke(
-      Send node,
-      FunctionElement setter,
-      NodeList arguments,
-      CallStructure callStructure,
-      _) {
+  ir.Expression handleStaticSetterInvoke(Send node, FunctionElement setter,
+      NodeList arguments, CallStructure callStructure, _) {
     return new ir.InvalidExpression();
   }
 
   @override
   ir.Expression handleStaticSetterSet(
       SendSet node, FunctionElement setter, Node rhs, _) {
     return buildStaticAccessor(null, setter)
         .buildAssignment(visitForValue(rhs), voidContext: isVoidContext);
   }
 
@@ skipping 586 matching lines @@
       : this(null, true, node, initializers);
 
   accept(ir.Visitor v) => throw "unsupported";
 
   visitChildren(ir.Visitor v) => throw "unsupported";
 
   String toString() {
     return "IrFunction($kind, $isConstructor, $node, $initializers)";
   }
 }