@Override
	protected void setChanged(boolean b) {
		super.setChanged(b);
		if (!b) {
			clearUndo(true);
		}
	}
Returns the undo stack depth.
(The number of items on the undo stack)
This method is for JUnits.
@return the undo stack depth
Ghidra/Framework/Project/src/main/java/ghidra/framework/data/DomainObjectAdapterDB.java