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
* <code>IEditorRegistry.getDefaultEditor(String)</code>.</li>
	 * <li>The operating system is consulted to determine if an in-place
	 * component editor is available (e.g. OLE editor on Win32 platforms).</li>
	 * <li>The operating system is consulted to determine if an external editor
	 * is available.</li>
	 * </ol>
	 * </p>
	 * 
	 * @param file
	 *            the file
	 * @param determineContentType
	 *            query the content type system for the content type of the file
	 * @return an editor descriptor, appropriate for opening the file
	 * @throws PartInitException
	 *             if no editor can be found
	 * @since 3.1
	 */
	public static IEditorDescriptor getEditorDescriptor(IFile file,
			boolean determineContentType) throws PartInitException {
		if (file == null) {
			throw new IllegalArgumentException();
		}
		return getEditorDescriptor(file.getName(), PlatformUI.getWorkbench()
				.getEditorRegistry(), getDefaultEditor(file,
				determineContentType));
	}
	/**
	 * Returns an editor descriptor appropriate for opening a file resource with
	 * the given name.
	 * <p>