DeskClock: Fixed the ringtone name display incorrect when delete music file

It only displays FALLBACKRING when set alarm ringtone by file explorer,
is caused by that it not handle the file uri which from file explorer
in getRingToneTitle method.

Add the judgement to get the file uri and get the right title of alarm
ringtone.

CRs-Fixed: 546747

Change-Id: I50ac325c1a636fb2a2985fbc15839fab9e31e0cc
DeskClock: handle call events on alarm

Alarm clock ringing while incoming call received.

When call ringing,alarm clock time arrived.Only Call ringing and no alarm
clock ringing.and after hang up the phone,alarm start ring.
When alarm ringing,receive a call,the alarm is stopped,and it can answer
or hang up the phone.after hang up the phone ,there has some reminder.

CRs-Fixed: 638868

Change-Id: If26b4f1f50f76ee4bd2873fefbda5d22551b002d