function handleFileCloseWindow(commandData) {
        return _handleWindowGoingAway(
            commandData,
            function () {
                window.close();
            },
            function () {
                // if fail, tell the app to abort any pending quit operation.
                // TODO: remove this if statement when we move to the new CEF3 shell
                if (brackets.app.abortQuit) {
                    brackets.app.abortQuit();
                }
            }
        );
    }
Confirms any unsaved changes, then closes the window