Bug 1506728 - Do requestFocus when performing explore by touch. r=snorp

Differential Revision: https://phabricator.services.mozilla.com/D11705

--HG--
extra : moz-landing-system : lando

mobile/android/geckoview/src/main/java/org/mozilla/geckoview/SessionAccessibility.java

@@ -624,6 +624,8 @@ public class SessionAccessibility {
             return false;
         }
 
+        mView.requestFocus();
+
         final GeckoBundle data = new GeckoBundle(2);
         data.putDoubleArray("coordinates", new double[] {event.getRawX(), event.getRawY()});
         mSession.getEventDispatcher().dispatch("GeckoView:AccessibilityExploreByTouch", data);