Bug 163345 [Field Assist] - API - Deprecate DecoratedField and related classes
If ControlDecoration is adopted in replacement of DecoratedField by all existing SDK clients, then we should deprecate DecoratedField.
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/FieldAssistColors.java
*/
	private static Map requiredFieldColorMap = new HashMap();
	/*
	 * Keys are colors we have created, values are the displays on which they
	 * were created.
	 */
	private static Map displays = new HashMap();
	/**
	 * Compute the RGB of the color that should be used for the background of a
	 * control to indicate that the control has an error. Because the color
	 * suitable for indicating an error depends on the colors set into the
	 * control, this color is always computed dynamically and provided as an RGB
	 * value. Clients who use this RGB to create a Color resource are
	 * responsible for managing the life cycle of the color.
	 * <p>
	 * This color is computed dynamically each time that it is queried. Clients
	 * should typically call this method once, create a color from the RGB
	 * provided, and dispose of the color when finished using it.
	 * 
	 * @param control
	 *            the control for which the background color should be computed.
	 * @return the RGB value indicating a background color appropriate for
	 *         indicating an error in the control.
	 */
	public static RGB computeErrorFieldBackgroundRGB(Control control) {
		/*
		 * Use a 10% alpha of the error color applied on top of the widget
		 * background color.
		 */
		Color dest = control.getBackground();