Bug 776649, part 1: Add mozIApplication in order to expose a hasPermission() method through it. r=fabrice

dom/apps/src/Webapps.jsm

@@ -698,7 +698,25 @@ let DOMApplicationRegistry = {
     for (let id in this.webapps) {
       let app = this.webapps[id];
       if (app.manifestURL == aManifestURL) {
-        return this._cloneAppObject(app);
+        let res = this._cloneAppObject(app);
+        res.hasPermission = function(permission) {
+          let localId = DOMApplicationRegistry.getAppLocalIdByManifestURL(
+            this.manifestURL);
+          let uri = Services.io.newURI(this.manifestURL, null, null);
+          let secMan = Cc["@mozilla.org/scriptsecuritymanager;1"]
+                       .getService(Ci.nsIScriptSecurityManager);
+          // XXX for the purposes of permissions checking, this helper
+          // should always be called on !isBrowser frames, so we
+          // assume false here.
+          let principal = secMan.getAppCodebasePrincipal(uri, localId,
+                                                         /*mozbrowser*/false);
+          let perm = Services.perms.testExactPermissionFromPrincipal(principal,
+                                                                     permission);
+          return (perm === Ci.nsIPermissionManager.ALLOW_ACTION);
+        };
+        res.QueryInterface = XPCOMUtils.generateQI([Ci.mozIDOMApplication,
+                                                    Ci.mozIApplication]);
+        return res;
       }
     }
 

dom/interfaces/apps/Makefile.in

@@ -15,6 +15,7 @@ XPIDL_MODULE   = dom_apps
 GRE_MODULE     = 1
 
 XPIDLSRCS =                               \
+            mozIApplication.idl \
             nsIDOMApplicationRegistry.idl \
             nsIAppsService.idl \
             nsIDOMMozApplicationEvent.idl \

dom/interfaces/apps/mozIApplication.idl

@@ -0,0 +1,19 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 et :
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsIDOMApplicationRegistry.idl"
+
+/**
+ * We expose Gecko-internal helpers related to "web apps" through this
+ * sub-interface.
+ */
+[scriptable, uuid(8de25e36-b4cb-4e89-9310-a199dce4e5f4)]
+interface mozIApplication: mozIDOMApplication
+{
+  /* Return true if this app has |permission|. */
+  boolean hasPermission(in string permission);
+};