VolumeZen: Prevent raising ringer volume in silent mode.

Instead of breaking out of silent mode when raising the volume
using the keys, prevent the change and display a visual hint up
in the user interface.

Bug:15330217
Change-Id: I74aae44319aadcd6db9841c7799967607f5a1617
diff --git a/packages/SystemUI/src/com/android/systemui/volume/VolumePanel.java b/packages/SystemUI/src/com/android/systemui/volume/VolumePanel.java
index 84cc1cdc..898b46e 100644
--- a/packages/SystemUI/src/com/android/systemui/volume/VolumePanel.java
+++ b/packages/SystemUI/src/com/android/systemui/volume/VolumePanel.java
@@ -898,6 +898,11 @@
                 mAudioManager.getRingerMode() == AudioManager.RINGER_MODE_VIBRATE) {
             sendMessageDelayed(obtainMessage(MSG_VIBRATE), VIBRATE_DELAY);
         }
+
+        // Pulse the slider icon if an adjustment was suppressed due to silent mode.
+        if (sc != null && (flags & AudioManager.FLAG_SHOW_SILENT_HINT) != 0) {
+            pulseIcon(sc.icon);
+        }
     }
 
     private boolean isShowing() {