Draw subtitles over the shutter.

This allows the demo app to display subtitles without video
(when there's no video, the shutter view does not hide itself).

demo/src/main/res/layout/player_activity.xml

@@ -31,15 +31,15 @@
         android:layout_height="match_parent"
         android:layout_height="match_parent"
         android:layout_gravity="center"/>
         android:layout_gravity="center"/>
 
 
-    <com.google.android.exoplayer.text.SubtitleLayout android:id="@+id/subtitles"
-        android:layout_width="match_parent"
-        android:layout_height="match_parent"/>
-
     <View android:id="@+id/shutter"
     <View android:id="@+id/shutter"
         android:layout_width="match_parent"
         android:layout_width="match_parent"
         android:layout_height="match_parent"
         android:layout_height="match_parent"
         android:background="@android:color/black"/>
         android:background="@android:color/black"/>
 
 
+    <com.google.android.exoplayer.text.SubtitleLayout android:id="@+id/subtitles"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"/>
+
   </com.google.android.exoplayer.AspectRatioFrameLayout>
   </com.google.android.exoplayer.AspectRatioFrameLayout>
 
 
   <LinearLayout
   <LinearLayout