Issue 3371080: fix VolumePanel in mute state

VolumePanel must take stream mute state into account before displaying
the update stream volume.

Change-Id: I03a1697c25fca3fa56f892e3d426d00906abeb79
diff --git a/core/java/android/view/VolumePanel.java b/core/java/android/view/VolumePanel.java
index bb5774f..2aa94dc 100644
--- a/core/java/android/view/VolumePanel.java
+++ b/core/java/android/view/VolumePanel.java
@@ -367,7 +367,10 @@
     }
 
     protected void onShowVolumeChanged(int streamType, int flags) {
-        int index = mAudioService.getStreamVolume(streamType);
+        int index = mAudioService.isStreamMute(streamType) ?
+                mAudioService.getLastAudibleStreamVolume(streamType)
+                : mAudioService.getStreamVolume(streamType);
+
 //        int message = UNKNOWN_VOLUME_TEXT;
 //        int additionalMessage = 0;
         mRingIsSilent = false;