Bug 156747 Adopt Resource.getDevice() in the JFace resource managers
SWT has recently added a Resource.getDevice() method. This allows several improvements to be made to the JFace resource managers: 1. The (inefficient and complex) heuristics that detect a device by creating temporary resources can be removed. 2. The one-argument descriptor factories that don't take a Device can be made just as efficient as the two-argument versions. 3. The descriptor factory methods that take a Device can be deprecated, since the second argument is no longer required and the one-argument version is just as efficient.
bundles/org.eclipse.jface/src/org/eclipse/jface/resource/ImageDataImageDescriptor.java
*/
    public ImageData getImageData() {
        return data;
    }
    
    /* (non-Javadoc)
     * @see Object#hashCode
     */
    public int hashCode() {
        return data.hashCode();
    }
    /* (non-Javadoc)
     * @see Object#equals
     */
    public boolean equals(Object obj) {
        if (!(obj instanceof ImageDataImageDescriptor)) {
			return false;
		} 
        
        ImageDataImageDescriptor imgWrap = (ImageDataImageDescriptor) obj;
       
        if (originalImage != null) {
            return imgWrap.originalImage == originalImage;
        }
        
        return (imgWrap.originalImage == null && data.equals(imgWrap.data));
    }
    
}