Integrating DialerRingtoneManager and InCallTonePlayer

This change makes the Call Waiting tone actually play during the
Call Waiting use case.

+ Plugging InCallTonePlayer into the DialerRingtoneManager in the
StatusBarNotifier
+ Test fixes
 + Added tests for when Dialer ringing is disabled
 + Added tests for DialerRingtoneManager#playCallWaitingTone
- Removed unneeded @NeededForTesting annotations from InCallTonePlayer
  since they won't be stipped out by proguard.
Change-Id: I49a83d2a7fe6edf5f9ec88db973a5f37e307f23a