dismiss the volume shade if the a11y stream goes away

... if the active stream was the a11y stream

Test: turn talkback on, change volume, turn talkback off before
the volume panel goes away
Fixes: 63252708

Change-Id: I5e03b17fd7408d28471919c45c910e634b415bbc
diff --git a/packages/SystemUI/src/com/android/systemui/volume/VolumeDialogImpl.java b/packages/SystemUI/src/com/android/systemui/volume/VolumeDialogImpl.java
index bc8c566..7f5c595 100644
--- a/packages/SystemUI/src/com/android/systemui/volume/VolumeDialogImpl.java
+++ b/packages/SystemUI/src/com/android/systemui/volume/VolumeDialogImpl.java
@@ -1059,7 +1059,12 @@
         public void onAccessibilityModeChanged(Boolean showA11yStream) {
             boolean show = showA11yStream == null ? false : showA11yStream;
             mShowA11yStream = show;
-            updateRowsH(getActiveRow());
+            VolumeRow activeRow = getActiveRow();
+            if (!mShowA11yStream && AudioManager.STREAM_ACCESSIBILITY == activeRow.stream) {
+                dismissH(Events.DISMISS_STREAM_GONE);
+            } else {
+                updateRowsH(activeRow);
+            }
 
         }
     };