Move dart2jslib parts into separate libraries.

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

Index: pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart
diff --git a/pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart b/pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart
index 506985e223949952c3b2ef4197d6eb4af8c6bf04..c25d8d7ad4c292832168b1f559c97bc0c2c19534 100644
--- a/pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart
+++ b/pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart
@@ -23,6 +23,8 @@ import '../dart2jslib.dart'
          TreeElementMapping;
 import '../elements/elements.dart';
 import '../native/native.dart' as native;
+import '../resolution/resolution.dart'
+    show TreeElementMapping;
 import '../tree/tree.dart' as ast
     show DartString,
          Node,
@@ -47,6 +49,7 @@ import '../util/util.dart'
          Setlet,
          Spannable;
 import '../js_backend/js_backend.dart' show Annotations, JavaScriptBackend;
+import '../world.dart' show ClassWorld;
 
 import 'inferrer_visitor.dart'
     show ArgumentsTypes,