Use WorldImpact for element dependencies in deferred_load

pkg/compiler/lib/src/helpers/debug_collection.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.
 
 part of dart2js.helpers;
 
 typedef void DebugCallback(String methodName, var arg1, var arg2);
 
 class DebugMap<K, V> implements Map<K, V> {
   final Map<K, V> map;
@@ skipping 215 matching lines @@
 
   bool contains(Object value) => set.contains(value);
 
   bool add(E value) {
     if (addCallback != null) {
       addCallback('add', value, null);
     }
     return set.add(value);
   }
 
-  void addAll(Iterable<E> elements) => set.addAll(elements);
+  void addAll(Iterable<E> elements) {
+    elements.forEach(add);
+  }
 
   bool remove(Object value) => set.remove(value);
 
   E lookup(Object object) => set.lookup(object);
 
   void removeAll(Iterable<Object> elements) => set.removeAll(elements);
 
   void retainAll(Iterable<Object> elements) => set.retainAll(elements);
 
   void removeWhere(bool test(E element)) => set.removeWhere(test);
@@ skipping 73 matching lines @@
     check(element, '$methodName: ');
   }
 
   void check(var element, [String text = '']) {
     String elementType = '${element.runtimeType}';
     if (runtimeTypes.contains(elementType)) return;
     throw '$name: $text$elementType'
           '${showObjects ? ' ($element)' : ''}';
   }
 }