Move dart_types to elements/resolution_types

tests/compiler/dart2js/kernel/impact_test.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 dart2js.kernel.impact_test;
 
 import 'package:async_helper/async_helper.dart';
 import 'package:compiler/src/commandline_options.dart';
 import 'package:compiler/src/common.dart';
 import 'package:compiler/src/common/names.dart';
 import 'package:compiler/src/common/resolution.dart';
 import 'package:compiler/src/compiler.dart';
 import 'package:compiler/src/constants/expressions.dart';
-import 'package:compiler/src/dart_types.dart';
+import 'package:compiler/src/elements/resolution_types.dart';
 import 'package:compiler/src/elements/elements.dart';
 import 'package:compiler/src/resolution/registry.dart';
 import 'package:compiler/src/resolution/tree_elements.dart';
 import 'package:compiler/src/ssa/kernel_impact.dart';
 import 'package:compiler/src/serialization/equivalence.dart';
 import 'package:compiler/src/universe/call_structure.dart';
 import 'package:compiler/src/universe/feature.dart';
 import 'package:compiler/src/universe/use.dart';
 import 'package:expect/expect.dart';
 import '../memory_compiler.dart';
@@ skipping 796 matching lines @@
         visitList(type.optionalParameterTypes),
         type.namedParameters,
         visitList(type.namedParameterTypes));
   }
 }
 
 /// Perform unaliasing of all typedefs nested within a [DartType].
 DartType unalias(DartType type) {
   return const Unaliaser().visit(type);
 }