Extract DartTypeVisitor and subclasses from resolution_types.

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

Index: pkg/compiler/lib/src/resolution/typedefs.dart
diff --git a/pkg/compiler/lib/src/resolution/typedefs.dart b/pkg/compiler/lib/src/resolution/typedefs.dart
index 8cad2d417f3b50457a91150e72e7b136f6914b22..16823a00547f64f76b2bcdeccafb75150ff3b8c4 100644
--- a/pkg/compiler/lib/src/resolution/typedefs.dart
+++ b/pkg/compiler/lib/src/resolution/typedefs.dart
@@ -49,7 +49,7 @@ class TypedefResolverVisitor extends TypeDefinitionVisitor {
 
 // 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 BaseDartTypeVisitor {
+class TypedefCyclicVisitor extends BaseResolutionDartTypeVisitor {
   final DiagnosticReporter reporter;
   final TypedefElementX element;
   bool hasCyclicReference = false;