Move dart_types to elements/resolution_types

tests/compiler/dart2js/related_types.dart

 // Copyright (c) 2015, 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 related_types;
 
 import 'package:compiler/src/commandline_options.dart';
 import 'package:compiler/src/compiler.dart';
 import 'package:compiler/src/core_types.dart';
-import 'package:compiler/src/dart_types.dart';
+import 'package:compiler/src/elements/resolution_types.dart';
 import 'package:compiler/src/diagnostics/diagnostic_listener.dart';
 import 'package:compiler/src/diagnostics/messages.dart';
 import 'package:compiler/src/elements/elements.dart';
 import 'package:compiler/src/filenames.dart';
 import 'package:compiler/src/resolution/semantic_visitor.dart';
 import 'package:compiler/src/tree/tree.dart';
 import 'package:compiler/src/universe/call_structure.dart';
 import 'package:compiler/src/universe/selector.dart';
 import 'package:compiler/src/world.dart';
 import 'memory_compiler.dart';
@@ skipping 388 matching lines @@
   ClassElement findClass(DartType type) => type.accept(this, null);
 
   @override
   ClassElement visitType(DartType type, _) => null;
 
   @override
   ClassElement visitInterfaceType(InterfaceType type, _) {
     return type.element;
   }
 }