Bug 174272 FileStoreEditorInput needs to be restorable
3.3 M5 The FileStoreEditorInput needs to restorable on startup. Therefore it needs to return an IPersistableElement and there needs to be an element factory.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/ide/IDE.java
* obtaining the default editor for that name.
	 * </p>
	 * 
	 * @param file
	 *            the file
	 * @param determineContentType
	 *            determine the content type for the given file
	 * @return the descriptor of the default editor, or <code>null</code> if
	 *         not found
	 * @since 3.1
	 */
	public static IEditorDescriptor getDefaultEditor(IFile file,
			boolean determineContentType) {
		
		IEditorRegistry editorReg = PlatformUI.getWorkbench()
				.getEditorRegistry();
		try {
			String editorID = file.getPersistentProperty(EDITOR_KEY);
			if (editorID != null) {
				IEditorDescriptor desc = editorReg.findEditor(editorID);
				if (desc != null) {
					return desc;
				}
			}
		} catch (CoreException e) {
			
		}
		IContentType contentType = null;
		if (determineContentType) {
			contentType = getContentType(file);