Bug 1015412 - [FMRadio] Implement new startup loading events

If I'm following you correctly, that means the navigation is the chrome, and you can fire `moz-chrome-dom-loaded` when you get the first opportunity (no need to wait for window load if there is no other markup to render or localization). Once the navigation events are bound, then fire `moz-chrome-interactive`.

Then the radio dialer bar, the main app content, isn't available in the page yet, but once the markup is injected, you can fire `moz-app-visually-complete`. Then once the content's events are bound, you can fire `moz-content-interactive`.