Remove direct access to enqueuer through use of WorldImpact

pkg/compiler/lib/src/deferred_load.dart

 // Copyright (c) 2014, 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 deferred_load;
 
 import 'common/backend_api.dart' show Backend;
 import 'common/tasks.dart' show CompilerTask;
 import 'common.dart';
 import 'compiler.dart' show Compiler;
@@ skipping 825 matching lines @@
                   : import;
               reporter.reportErrorMessage(failingImport.prefix,
                   MessageKind.DEFERRED_LIBRARY_DUPLICATE_PREFIX);
             }
             usedPrefixes.add(prefix);
           }
         }
       });
     }
     if (isProgramSplit) {
-      isProgramSplit = compiler.backend.enableDeferredLoadingIfSupported(
-          compiler.enqueuer.resolution, lastDeferred);
+      isProgramSplit =
+          compiler.backend.enableDeferredLoadingIfSupported(lastDeferred);
     }
   }
 
   /// If [send] is a static send with a deferred element, returns the
   /// [PrefixElement] that the first prefix of the send resolves to.
   /// Otherwise returns null.
   ///
   /// Precondition: send must be static.
   ///
   /// Example:
@@ skipping 194 matching lines @@
 
   bool operator ==(other) {
     if (other is! _DeclaredDeferredImport) return false;
     return declaration == other.declaration;
   }
 
   int get hashCode => declaration.hashCode * 17;
 
   String toString() => '$declaration';
 }