This class is designed to be mixed with a WebWindow subclass.
This isn't a complete replacement for BannerWindow, because the layout model for the Web UI is different from the banner window model (the Web UI model is better and more flexible). This class implements the parts of the BannerWindow API related to the stream-oriented output to the window, so you shouldn't have to change anything that writes HTML text to the window. However, you will have to rework code that sets up the window's layout to use the Web UI model.
WebBannerWin : OutputStreamWindow