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
* @param saveable the saveable
		 * @return whether the given saveable contains any resources that
		 * are descendants of the root resources
		 */
		private boolean isDescendantOfRoots(Saveable saveable) {
			
			ResourceMapping mapping = ResourceUtil.getResourceMapping(saveable);
			if (mapping != null) {
				try {
					ResourceTraversal[] traversals = mapping.getTraversals(
							ResourceMappingContext.LOCAL_CONTEXT, null);
					for (int i = 0; i < traversals.length; i++) {
						ResourceTraversal traversal = traversals[i];
						IResource[] resources = traversal.getResources();
						for (int j = 0; j < resources.length; j++) {
							IResource resource = resources[j];
							if (isDescendantOfRoots(resource)) {
								return true;
							}
						}
					}
				} catch (CoreException e) {
					IDEWorkbenchPlugin
							.log(
									NLS
											.bind(
													"An internal error occurred while determining the resources for {0}", saveable.getName()), e); 
				}
			} else {