Use string SharedPreferences key for update ringtone.

Instead of using the preference, deal directly with the key.

I changed the logic so that it will return null/silent as the
ringtone uri if the key is null. Because, technically, one could
call the function with a "type" expecting a valid return type,
but not provide a key.

Bug: 18232725
Change-Id: Ifb3d517ef8b0a5ddba388f2e0d471874f7b4b235
1 file changed
tree: d3ad247afb0d9a245d2a1761fd2c5eb0bdfa3425
  1. res/
  2. src/
  3. Android.mk
  4. AndroidManifest.xml