Bug 1498934: Fix handler app enumeration issue. r=Gijs

Since gioApps here is a plain nsIArray, it doesn't have any intrinsic type
information, and we only get the correct interfaces if they've already been
queried. Adding an interface parameter to the enumerate() call fixes the
issue.

This code is apparently untested, or incompletely tested.

Differential Revision: https://phabricator.services.mozilla.com/D9672

--HG--
extra : rebase_source : ed20681225d5357806bb33dd760dc8f01da58cdf

toolkit/mozapps/handling/content/dialog.js

@@ -154,7 +154,7 @@ var dialog = {
       let gIOSvc = Cc["@mozilla.org/gio-service;1"]
                      .getService(Ci.nsIGIOService);
       var gioApps = gIOSvc.getAppsForURIScheme(this._URI.scheme);
-      for (let handler of gioApps.enumerate()) {
+      for (let handler of gioApps.enumerate(Ci.nsIHandlerApp)) {
         // OS handler share the same name, it's most likely the same app, skipping...
         if (handler.name == this._handlerInfo.defaultDescription) {
           continue;