Bug 184423 [JFace] ColorRegistry.getRGB(String) can return null
I20070427-0010 ColorRegistry.getRGB(String) can return null but this is not speced in the Javadoc.
bundles/org.eclipse.jface/src/org/eclipse/jface/resource/ColorRegistry.java
/*******************************************************************************
 * Copyright (c) 2003, 2006 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jface.resource;
import java.util.ArrayList;
import java.util.Collections;