Use mappedTrackInfo local

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=178216750

demos/main/src/main/java/com/google/android/exoplayer2/demo/PlayerActivity.java

@@ -233,8 +233,8 @@ public class PlayerActivity extends Activity implements OnClickListener,
     } else if (view.getParent() == debugRootView) {
       MappedTrackInfo mappedTrackInfo = trackSelector.getCurrentMappedTrackInfo();
       if (mappedTrackInfo != null) {
-        trackSelectionHelper.showSelectionDialog(this, ((Button) view).getText(),
-            trackSelector.getCurrentMappedTrackInfo(), (int) view.getTag());
+        trackSelectionHelper.showSelectionDialog(
+            this, ((Button) view).getText(), mappedTrackInfo, (int) view.getTag());
       }
     }
   }