Add adjustments to allow for TvMediaOutputDialog.

In order for TV to have its own separate version of the
MediaOutputDialog the dialog factory needs to be extensible.
As TV will be re-using the controller, some methods need to have their
access modifiers changed.

Bug: 292064212
Test: build successfully

Change-Id: I84f631897adaae11625673ee601bcd3072905d7a