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/RGBColorDescriptor.java
private RGB color;
    private Color originalColor = null;
    private Device originalDevice = null;
    
    /**
     * Creates a new RGBColorDescriptor given some RGB values
     * 
     * @param color RGB values (not null)
     */
    public RGBColorDescriptor(RGB color) {
        this.color = color;
    }
    
	/**
     * Creates a new RGBColorDescriptor that describes an existing color. 
     * 
     * @since 3.1