anchor.diff:    }
   }
   
  +class _ElementByIdFinder extends GeneralizingElementVisitor {
  +  final int _id;
  +  Element result;
  +
  +  _ElementByIdFinder(this._id);
  +
  +  @override
  +  visitElement(Element element) {
  +    if (element.id == _id) {
  +      result = element;
  +      throw new _ElementByIdFinderException();
  +    }
  +    super.visitElement(element);
  +  }
  +}
  +
  +class _ElementByIdFinderException {
  +}
  +
   class _PolymerHtmlUnitBuilder_findTagDartElement extends
       RecursiveElementVisitor<Object> {
     final PolymerHtmlUnitBuilder PolymerHtmlUnitBuilder_this;
  
positive.code:     }
      return changedSources.length > 0;
    }
  }
  
  class _ElementByIdFinder extends GeneralizingElementVisitor {
    final int _id;
    Element result;
  
    _ElementByIdFinder(this._id);
  
    @override
    visitElement(Element element) {
      if (element.id == _id) {
        result = element;
        throw new _ElementByIdFinderException();
      }
      super.visitElement(element);
    }
  }
  
  class _ElementByIdFinderException {
  }
  
  /**
  
negative.code:       return true;
      }
      return source.exists();
    }
  
    Element findElementById(int id) {
      _ElementByIdFinder finder = new _ElementByIdFinder(id);
      try {
        MapIterator<Source, SourceEntry> iterator = _cache.iterator();
        while (iterator.moveNext()) {
          SourceEntry sourceEntry = iterator.value;
          if (sourceEntry.kind == SourceKind.LIBRARY) {
            DartEntry dartEntry = sourceEntry;
            LibraryElement library = dartEntry.getValue(DartEntry.ELEMENT);
            if (library != null) {
              library.accept(finder);
            }
          }
        }
      } on _ElementByIdFinderException catch (e) {
        return finder.result;
      }
      return null;
    }
  
    @override
  