Bug 53881 [Colors] Color/Gradient registry should return default values.
There should be default values for when a user does .get() on a bad key.
bundles/org.eclipse.jface/src/org/eclipse/jface/resource/FontRegistry.java
}
	};
	/**
	 * Creates an empty font registry.
	 * <p>
	 * There must be an SWT Display created in the current 
	 * thread before calling this method.
	 * </p>
	 */
	public FontRegistry() {
		Display display = Display.getCurrent();
		Assert.isNotNull(display);
		hookDisplayDispose(display);
	}
	/**
	 * Creates a font registry and initializes its content from
	 * a property file.
	 * <p>
	 * There must be an SWT Display created in the current 
	 * thread before calling this method.
	 * </p>
	 * <p>
	 * The OS name (retrieved using <code>System.getProperty("os.name")</code>)
	 * is converted to lowercase, purged of whitespace, and appended 
	 * as suffix (separated by an underscore <code>'_'</code>) to the given 
	 * location string to yield the base name of a resource bundle
	 * acceptable to <code>ResourceBundle.getBundle</code>.
	 * The standard Java resource bundle mechanism is then used to locate
	 * and open the appropriate properties file, taking into account
	 * locale specific variations.