Decouple WorkItem from Compiler

pkg/compiler/lib/src/universe/world_builder.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 'dart:collection';
 
 import '../cache_strategy.dart';
 import '../common.dart';
@@ skipping 618 matching lines @@
     }
     switch (staticUse.kind) {
       case StaticUseKind.SUPER_FIELD_SET:
       case StaticUseKind.FIELD_SET:
         fieldSetters.add(element);
         break;
       case StaticUseKind.SUPER_TEAR_OFF:
         methodsNeedingSuperGetter.add(element);
         break;
       case StaticUseKind.GENERAL:
+      case StaticUseKind.DIRECT_USE:
       case StaticUseKind.STATIC_TEAR_OFF:
       case StaticUseKind.FIELD_GET:
       case StaticUseKind.CONSTRUCTOR_INVOKE:
       case StaticUseKind.CONST_CONSTRUCTOR_INVOKE:
       case StaticUseKind.REDIRECTION:
         break;
       case StaticUseKind.CLOSURE:
         allClosures.add(element);
         break;
       case StaticUseKind.DIRECT_INVOKE:
@@ skipping 255 matching lines @@
     switch (staticUse.kind) {
       case StaticUseKind.STATIC_TEAR_OFF:
         staticFunctionsNeedingGetter.add(element);
         break;
       case StaticUseKind.SUPER_TEAR_OFF:
         methodsNeedingSuperGetter.add(element);
         break;
       case StaticUseKind.SUPER_FIELD_SET:
       case StaticUseKind.FIELD_SET:
       case StaticUseKind.GENERAL:
+      case StaticUseKind.DIRECT_USE:
       case StaticUseKind.CLOSURE:
       case StaticUseKind.FIELD_GET:
       case StaticUseKind.CONSTRUCTOR_INVOKE:
       case StaticUseKind.CONST_CONSTRUCTOR_INVOKE:
       case StaticUseKind.REDIRECTION:
       case StaticUseKind.DIRECT_INVOKE:
         break;
     }
   }
 
   void forgetElement(Element element, Compiler compiler) {
     _directlyInstantiatedClasses.remove(element);
     if (element is ClassElement) {
       assert(invariant(element, element.thisType.isRaw,
           message: 'Generic classes not supported (${element.thisType}).'));
       _instantiatedTypes..remove(element.rawType)..remove(element.thisType);
     }
   }
 }