Move dart2jslib parts into separate libraries.

pkg/compiler/lib/src/inferrer/inferrer_visitor.dart

 // Copyright (c) 2013, 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 inferrer_visitor;
 
+import 'dart:collection' show IterableMixin;
+
 import '../constants/constant_system.dart';
 import '../constants/expressions.dart';
 import '../dart2jslib.dart' hide Selector, TypedSelector;
 import '../dart_types.dart';
 import '../elements/elements.dart';
 import '../resolution/operators.dart';
+import '../resolved_visitor.dart';
 import '../tree/tree.dart';
+import '../types/types.dart' show TypeMask;
+import '../types/constants.dart' show computeTypeMask;
 import '../universe/universe.dart';
 import '../util/util.dart';
-import '../types/types.dart' show TypeMask;
-import '../types/constants.dart' show computeTypeMask;
-import 'dart:collection' show IterableMixin;
+import '../world.dart' show ClassWorld;
 
 /**
  * The interface [InferrerVisitor] will use when working on types.
  */
 abstract class TypeSystem<T> {
   T get dynamicType;
   T get nullType;
   T get intType;
   T get uint31Type;
   T get uint32Type;
@@ skipping 1419 matching lines @@
     return type;
   }
 
   T visitCascade(Cascade node) {
     // Ignore the result of the cascade send and return the type of the cascade
     // receiver.
     visit(node.expression);
     return cascadeReceiverStack.removeLast();
   }
 }