Remove black titlebar from maximized window

Windows opened by window.open appear to get a black titlebar, while
windows opened by local_path in the application's manifest get compact
maximize/close controls with no titlebar. This change opens the crosh
shell window using a javascript redirect from a window loaded from
local_path, getting rid of the titlebar.

Regressions:
* window has no title
* window has no default size
* app opens in new tab by default