Merge kernel closure conversion into the Dart SDK

pkg/kernel/lib/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 file.
 library kernel.ast.visitor;
 
 import 'ast.dart';
 
 abstract class ExpressionVisitor<R> {
   R defaultExpression(Expression node) => null;
   R defaultBasicLiteral(BasicLiteral node) => defaultExpression(node);
@@ skipping 217 matching lines @@
 
 class MemberReferenceVisitor<R> {
   R defaultMemberReference(Member node) => null;
 
   R visitFieldReference(Field node) => defaultMemberReference(node);
   R visitConstructorReference(Constructor node) => defaultMemberReference(node);
   R visitProcedureReference(Procedure node) => defaultMemberReference(node);
 }
 
 class Visitor<R> extends TreeVisitor<R>
-    implements
-        DartTypeVisitor<R>,
-        MemberReferenceVisitor<R> {
+    implements DartTypeVisitor<R>, MemberReferenceVisitor<R> {
   /// The catch-all case, except for references.
   R defaultNode(Node node) => null;
   R defaultTreeNode(TreeNode node) => defaultNode(node);
 
   /// Inferred values
   R visitInferredValue(InferredValue node) => defaultNode(node);
 
   // DartTypes
   R defaultDartType(DartType node) => defaultNode(node);
   R visitInvalidType(InvalidType node) => defaultDartType(node);
@@ skipping 55 matching lines @@
   /// By default, recursion stops at this point.
   DartType visitDartType(DartType node) => node;
 
   Supertype visitSupertype(Supertype node) => node;
 
   TreeNode defaultTreeNode(TreeNode node) {
     node.transformChildren(this);
     return node;
   }
 }