Bug 1373945 - Skip test_beaconPreflightWithCustomContentType.html on Android, for intermittent failures; r=me,test-only

dom/tests/mochitest/beacon/mochitest.ini

@@ -8,6 +8,7 @@ support-files = beacon-frame.html
 [test_beacon.html]
 [test_beaconFrame.html]
 [test_beaconPreflightWithCustomContentType.html]
+skip-if = toolkit == 'android'  # Bug 1373945
 [test_beaconContentPolicy.html]
 [test_beaconOriginHeader.html]
 [test_beaconRedirect.html]