Bug 126839 [DataBinding] IObservable refactoring
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/internal/databinding/swt/ButtonUpdatableValue.java
private final Button button;
	private Listener updateListener = new Listener() {
		public void handleEvent(Event event) {
			fireChangeEvent(ChangeEvent.CHANGE, null, new Boolean(button
					.getSelection()));
		}
	};
	/**
	 * @param button
	 * @param updatePolicy
	 */
	public ButtonUpdatableValue(Button button, int updatePolicy) {