public Builder addCustomDrawableFactory(DrawableFactory factory) {
      if (mCustomDrawableFactories == null) {
        mCustomDrawableFactories = new ArrayList<>();
      }
      mCustomDrawableFactories.add(factory);
      return this;
    }
Add a custom drawable factory that will be used to create Drawables for {@link
com.facebook.imagepipeline.image.CloseableImage}s.

@param factory the factory to use
@return the builder
drawee-backends/drawee-pipeline/src/main/java/com/facebook/drawee/backends/pipeline/DraweeConfig.java