Workaround for SurfaceView not being hidden properly

This appears to be fixed in Oreo, but given how harmless
the workaround is we can probably just apply it on all
API levels to be sure.

Issue: #3160

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=167709070

library/ui/src/main/java/com/google/android/exoplayer2/ui/SimpleExoPlayerView.java

@@ -428,6 +428,15 @@ public final class SimpleExoPlayerView extends FrameLayout {
     }
   }
 
+  @Override
+  public void setVisibility(int visibility) {
+    super.setVisibility(visibility);
+    if (surfaceView instanceof SurfaceView) {
+      // Work around https://github.com/google/ExoPlayer/issues/3160
+      surfaceView.setVisibility(visibility);
+    }
+  }
+
   /**
    * Sets the resize mode.
    *