Delay unmuting on volume down

This allows the user to turn the volume down before a stream is unmuted by
delaying the unmute call while volume down requests are still being made.

bug:19297183
Change-Id: I65a8e489eb4cbfeace4f539103ee0025584102da
diff --git a/packages/SystemUI/src/com/android/systemui/volume/VolumePanel.java b/packages/SystemUI/src/com/android/systemui/volume/VolumePanel.java
index acdcfc1..19a631a 100644
--- a/packages/SystemUI/src/com/android/systemui/volume/VolumePanel.java
+++ b/packages/SystemUI/src/com/android/systemui/volume/VolumePanel.java
@@ -602,7 +602,7 @@
 
     private int getStreamVolume(int streamType) {
         if (streamType == STREAM_MASTER) {
-            return mAudioManager.getMasterVolume();
+            return mAudioManager.getLastAudibleMasterVolume();
         } else if (streamType == STREAM_REMOTE_MUSIC) {
             if (mStreamControls != null) {
                 StreamControl sc = mStreamControls.get(streamType);
@@ -613,7 +613,7 @@
             }
             return -1;
         } else {
-            return mAudioManager.getStreamVolume(streamType);
+            return mAudioManager.getLastAudibleStreamVolume(streamType);
         }
     }