Bug 1279332 - Document that onTargetSelected should be run on the UI thread r=grisha

MozReview-Commit-ID: IJ7UItFhvtE

--HG--
extra : rebase_source : 21c8447deae4c7fee221ecfb7cc73076f88f0c26

mobile/android/base/java/org/mozilla/gecko/widget/GeckoActionProvider.java

@@ -51,6 +51,8 @@ public class GeckoActionProvider {
      * A listener to know when a target was selected.
      * When setting a provider, the activity can listen to this,
      * to close the menu.
+     *
+     * Is run on the UI thread.
      */
     public interface OnTargetSelectedListener {
         public void onTargetSelected();