Extract DartTypeVisitor and subclasses from resolution_types.

pkg/compiler/lib/src/compiler.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.
 
 library dart2js.compiler_base;
 
 import 'dart:async' show Future;
 
 import '../compiler_new.dart' as api;
 import 'closure.dart' as closureMapping show ClosureTask;
@@ skipping 16 matching lines @@
 import 'diagnostics/code_location.dart';
 import 'diagnostics/diagnostic_listener.dart' show DiagnosticReporter;
 import 'diagnostics/invariant.dart' show REPORT_EXCESS_RESOLUTION;
 import 'diagnostics/messages.dart' show Message, MessageTemplate;
 import 'dump_info.dart' show DumpInfoTask;
 import 'elements/elements.dart';
 import 'elements/entities.dart';
 import 'elements/modelx.dart' show ErroneousElementX;
 import 'elements/resolution_types.dart'
     show
+        DartTypes,
         ResolutionDartType,
         ResolutionDynamicType,
         ResolutionFunctionType,
         ResolutionInterfaceType,
         Types;
 import 'enqueue.dart' show Enqueuer, EnqueueTask, ResolutionEnqueuer;
 import 'environment.dart';
 import 'id_generator.dart';
 import 'io/source_information.dart' show SourceInformation;
 import 'js_backend/backend.dart' show JavaScriptBackend;
@@ skipping 32 matching lines @@
 import 'util/util.dart' show Link;
 import 'world.dart' show ClosedWorld, ClosedWorldRefiner, ClosedWorldImpl;
 
 typedef CompilerDiagnosticReporter MakeReporterFunction(
     Compiler compiler, CompilerOptions options);
 
 abstract class Compiler {
   Measurer get measurer;
 
   final IdGenerator idGenerator = new IdGenerator();
-  Types types;
+  DartTypes types;
   CommonElements _commonElements;
   _CompilerElementEnvironment _elementEnvironment;
   CompilerDiagnosticReporter _reporter;
   CompilerResolution _resolution;
   ParsingContext _parsingContext;
 
   ImpactStrategy impactStrategy = const ImpactStrategy();
 
   /**
    * Map from token to the first preceding comment token.
@@ skipping 1868 matching lines @@
   ResolutionFunctionType getLocalFunctionType(LocalFunctionElement function) {
     return function.type;
   }
 
   @override
   ResolutionDartType getUnaliasedType(ResolutionDartType type) {
     type.computeUnaliased(_resolution);
     return type.unaliased;
   }
 }