[MediaRenderer] Fix lost renderer and added Status Changed signal

Remove renderers when a lost renderer signal is received. And
add support for Status Changed signal on the MediaController.

BUG=XWALK-2532
BUG=XWALK-2574
```
if (callback != null &&
    isValidMediaControllerEventType(type) &&
    ~~this.media_controller_listeners[type].indexOf(callback)
```