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
*/
	private void put(
		String symbolicName,
		FontData[] fontData,
		boolean update) {
		Assert.isNotNull(symbolicName);
		Assert.isNotNull(fontData);
		FontData[] existing = (FontData[]) stringToFontData.get(symbolicName);
		if (Arrays.equals(existing, fontData))
			return;
		Font oldFont = (Font) stringToFont.remove(symbolicName);
		stringToFontData.put(symbolicName, fontData);
		if (update)
			fireMappingChanged(symbolicName,existing,fontData);
		if (oldFont == defaultFont())
			return;
		if (oldFont != null)
			staleFonts.add(oldFont);
	}
	/**
	 * Reads the resource bundle.  This puts FontData[] objects
	 * in the mapping table.  These will lazily be turned into
	 * real Font objects when requested.
	 */
	private void readResourceBundle(ResourceBundle bundle, String bundleName)
		throws MissingResourceException {
		Enumeration keys = bundle.getKeys();
		while (keys.hasMoreElements()) {
			String key = (String) keys.nextElement();
			int pos = key.lastIndexOf('.');