anchor.diff:  
     FilterRegisterEvent(this.name, this.filter);
   }
  -
  -/// Textures register event.
  -/// Will be reaised when all textures will be registered.
  -class TexturesRegisterEvent {
  -  /// All registered textures.
  -  Map<String, Texture> textures;
  -
  -  TexturesRegisterEvent(this.textures);
  -}
  -
  -/// Filter register event.
  -/// Will be reaised when all filters will be registered.
  -class FiltersRegisterEvent {
  -  /// All registered filters.
  -  Map<String, Filter> filters;
  -
  -  FiltersRegisterEvent(this.filters);
  -}
  
positive.code: 
  /// Register game resourses.
  class AssetManager {
    /// Stream controller for [onTextureRegister] stream.
    StreamController<TextureRegisterEvent> _onTextureRegisterCtrl;
  
    /// Stream controller for [onTexturesRegister] stream.
    StreamController<TexturesRegisterEvent> _onTexturesRegisterCtrl;
  
    /// Stream controller for [onFilterRegister] stream.
    StreamController<FilterRegisterEvent> _onFilterRegisterCtrl;
  
    /// Stream controller for [onFiltersRegister] stream.
    StreamController<FiltersRegisterEvent> _onFiltersRegisterCtrl;
  
    /// Invokes on [registerFilter] and used by [Renderer] itself to proxy
    /// registration to [FilterManager].
    Function _onFilterRegister;
  
negative.code:         filters = <String, Filter>{} {
      _onFilterRegister = onFilterRegister;
      _onTextureRegister = onTextureRegister;
    }
  
    /// Register texture.
    void registerTexture(String name, Texture texture) {
      if (textures.containsKey(name)) {
        window.console.warn("Texture with name \"${name}\" already registered.");
      } else {
        textures[name] = texture;
        _onTextureRegister(new TextureRegisterEvent(name, texture));
      }
    }
  
    /// Register multiply textures.
    void registerTextures(Map<String, Texture> textures) {
      textures.forEach(registerTexture);
    }
  
    /// Register filter.
    Future registerFilter(String name, Filter filter) async {
      if (filters.containsKey(name)) {
        window.console.warn("Filter with name \"${name}\" already registered.");
      } else {
        filters[name] = filter;
        _onFilterRegister(new FilterRegisterEvent(name, filter));
      }
    }
  
    /// Register multply filters.
    Future registerFilters(Map<String, Filter> filters) async {
      filters.forEach(registerFilter);
    }
  }
  
  /// Texture register event.
  