Refactor DartTypeVisitor and ElementVisitor.

pkg/compiler/lib/src/resolution/members.dart

 // Copyright (c) 2012, 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 resolution;
 
 abstract class TreeElements {
   AnalyzableElement get analyzedElement;
   Iterable<Node> get superUses;
 
@@ skipping 4120 matching lines @@
 
     void checkCyclicReference() {
       element.checkCyclicReference(compiler);
     }
     addDeferredAction(element, checkCyclicReference);
   }
 }
 
 // TODO(johnniwinther): Replace with a traversal on the AST when the type
 // annotations in typedef alias are stored in a [TreeElements] mapping.
-class TypedefCyclicVisitor extends DartTypeVisitor {
+class TypedefCyclicVisitor extends BaseDartTypeVisitor {
   final Compiler compiler;
   final TypedefElementX element;
   bool hasCyclicReference = false;
 
   Link<TypedefElement> seenTypedefs = const Link<TypedefElement>();
 
   int seenTypedefsCount = 0;
 
   Link<TypeVariableElement> seenTypeVariables =
       const Link<TypeVariableElement>();
@@ skipping 961 matching lines @@
 }
 
 /// The result for the resolution of the `assert` method.
 class AssertResult implements ResolutionResult {
   const AssertResult();
 
   Element get element => null;
 
   String toString() => 'AssertResult()';
 }