Called by Agentry to ask if the extension view needs to auto-size to accommodate the displayed data.
public AutosizeBehavior getAutosizeBehavior ()
If this returns Autosize_WrapContent and the field's height in the editor is set to "Auto", Agentry will call getContentHeightForAutosizing to get the needed height from the extension. If this returns Autosize_FillVisible, Agentry will size the field to fill the available screen area. If this returns Autosize_None, Agentry will size the extension without asking.
This works in conjunction with FieldModel.isAutosizeSupported() which allows the extension to ask if the editor definitions support autosizing. autosizeBehavior() is Agentry's way of asking if the extension is able to handle autosizing.