Simplify the selector map and get rid of the partial type tree.

sdk/lib/_internal/compiler/implementation/universe/universe.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 universe;
 
 import '../closure.dart';
 import '../elements/elements.dart';
 import '../dart2jslib.dart';
 import '../dart_types.dart';
 import '../tree/tree.dart';
 import '../util/util.dart';
 import '../js/js.dart' as js;
 
 part 'function_set.dart';
-part 'partial_type_tree.dart';
 part 'selector_map.dart';
 
 class Universe {
   /**
    * Documentation wanted -- johnniwinther
    *
    * Invariant: Elements are declaration elements.
    */
   // TODO(karlklose): these sets should be merged.
   final Set<ClassElement> instantiatedClasses;
@@ skipping 504 matching lines @@
       if (cls.isSubclassOf(other)) {
         // Resolve an invocation of [element.name] on [self]. If it
         // is found, this selector is a candidate.
         return hasElementIn(self, element) && appliesUntyped(element, compiler);
       }
     }
 
     return false;
   }
 }