This is found by Henry. In Bug 674741, a static function called Navigator::HasNfcSupport is added, but actually it's never been called. When I try to call the function from MozNfc.webidl, I spotted some mochitest error. The error should be caused by 1. win is null when running XBL test. This problem is also met by Henry in https://bugzilla.mozilla.org/show_bug.cgi?id=946815#c11, also there should be another bug Bug 946815 is tracking permission bugs during mochitest. 2. manifest.webapp didn't add 'nfc' permission.

Try : https://tbpl.mozilla.org/?tree=Try&rev=5ae05be0a8de No sure if I also have to update gaia/test_external_apps/mochitest/manifest.webapp as well.

Comment on attachment 8346434 [details] [diff] [review] WIP - Patch. Hi BZ Since you also mentioned the permission problem in https://bugzilla.mozilla.org/show_bug.cgi?id=939056#c43 So my proposal is to fix HasNfcSupport to use principal and update MozNfc.webidl and add nfc permission in manifest.webapp. Then in Bug 939056(which you already r+ed), since MozNfc will be only available on some device, we'll need another patch to remove MozNfc from dom/tests/mochitest/general/test_interfaces.html. And add the MozNfc back to the test_interfaces.html when emulator (or emulator on JellyBean) supports NFC.(Could be another bug) Or should we simply add another patch to remove MozNfc from test_interfaces.html in Bug 939056 ? (which means we don't have to use principal to check permission in Navigator::HasNfcSupport.) How do you think?

Comment on attachment 8346434 [details] [diff] [review] WIP - Patch. Well, which behavior do we actually want? Should this interface be available in XBL scopes or not?

(In reply to Boris Zbarsky [:bz] from comment #4) > Comment on attachment 8346434 [details] [diff] [review] > WIP - Patch. > > Well, which behavior do we actually want? Should this interface be > available in XBL scopes or not? I don't know XBL well, but I think it should *not* in XBL scope, but it seems from the test_interfaces.html the test case would like MozNfc to be in the XBL scope. But I also found other B2G API are also in XBL scope like MozIccManager, MobileConnection, ...etc. Thanks for your comments anyway, but I just found MozNfc has been removed from test_interfaces.html in Bug 946047. (Which I don't think it's correct, at least it should be removed in Bug 939056), so I'll cancel the feedback and close this bug as WONTFIX first. Thank you, BZ. :)