Make the universe parts into small libraries.

pkg/compiler/lib/src/enqueue.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.enqueue;
 
 import 'dart:collection' show
     Queue;
 
 import 'common/names.dart' show
@@ skipping 37 matching lines @@
     TypedElement,
     TypedefElement;
 import 'js/js.dart' as js;
 import 'native/native.dart' as native;
 import 'resolution/members.dart' show
     ResolverVisitor;
 import 'tree/tree.dart' show
     Send;
 import 'types/types.dart' show
     TypeMaskStrategy;
+import 'universe/selector.dart' show
+    Selector;
 import 'universe/universe.dart';
 import 'util/util.dart' show
     Link,
     Setlet;
 
 typedef ItemCompilationContext ItemCompilationContextCreator();
 
 class EnqueueTask extends CompilerTask {
   final ResolutionEnqueuer resolution;
   final CodegenEnqueuer codegen;
@@ skipping 1001 matching lines @@
   @override
   void processStaticUse(Enqueuer enqueuer, Element element) {
     enqueuer.registerStaticUseInternal(element);
   }
 
   @override
   void processSelector(Enqueuer enqueuer, UniverseSelector selector) {
     enqueuer.handleUnseenSelectorInternal(selector);
   }
 }