Revert "Merge pull request #6816 from ian-liu/clock/Bug814632_silent_…

…alarm_screen_underneath_call_screen"

This reverts commit df38f79, reversing
changes made to 1734754.

apps/clock/js/onring.js

@@ -36,14 +36,9 @@ var RingView = {
   init: function rv_init() {
     this.setAlarmTime();
     this.setAlarmLabel();
-    // If mozHidden is true in init state, 
-    // it means that alarm screen underneath the oncall screen.
-    // Don't let the alarm ring and vibrate.
-    if (!document.mozHidden) {
-      this.setWakeLockEnabled(true);
-      this.ring();
-      this.vibrate();
-    }
+    this.setWakeLockEnabled(true);
+    this.ring();
+    this.vibrate();
     document.addEventListener('mozvisibilitychange', this);
     this.snoozeButton.addEventListener('click', this);
     this.closeButton.addEventListener('click', this);
@@ -112,22 +107,14 @@ var RingView = {
   stopAlarmNotification: function rv_stopAlarmNotification(action) {
     switch (action) {
     case 'ring':
-      if (this._ringtonePlayer)
-        this._ringtonePlayer.pause();
-
+      this._ringtonePlayer.pause();
       break;
     case 'vibrate':
-      if (this._vibrateInterval)
-        window.clearInterval(this._vibrateInterval);
-
+      window.clearInterval(this._vibrateInterval);
       break;
     default:
-      if (this._ringtonePlayer)
-        this._ringtonePlayer.pause();
-
-      if (this._vibrateInterval)
-        window.clearInterval(this._vibrateInterval);
-
+      this._ringtonePlayer.pause();
+      window.clearInterval(this._vibrateInterval);
       break;
     }
     this.setWakeLockEnabled(false);