diff -r 000000000000 -r 6474c204b198 browser/metro/base/content/helperui/OfflineApps.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/metro/base/content/helperui/OfflineApps.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,81 @@
+/* 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/. */
+
+/*
+ * Provide supports for Offline Applications
+ */
+var OfflineApps = {
+  offlineAppRequested: function(aRequest, aTarget) {
+    if (!Services.prefs.getBoolPref("browser.offline-apps.notify"))
+      return;
+
+    let currentURI = Services.io.newURI(aRequest.location, aRequest.charset, null);
+
+    // don't bother showing UI if the user has already made a decision
+    if (Services.perms.testExactPermission(currentURI, "offline-app") != Ci.nsIPermissionManager.UNKNOWN_ACTION)
+      return;
+
+    try {
+      if (Services.prefs.getBoolPref("offline-apps.allow_by_default")) {
+        // all pages can use offline capabilities, no need to ask the user
+        return;
+      }
+    } catch(e) {
+      // this pref isn't set by default, ignore failures
+    }
+
+    let host = currentURI.asciiHost;
+    let notificationID = "offline-app-requested-" + host;
+    let notificationBox = Browser.getNotificationBox(aTarget);
+
+    let notification = notificationBox.getNotificationWithValue(notificationID);
+    let strings = Strings.browser;
+    if (notification) {
+      notification.documents.push(aRequest);
+    } else {
+      let buttons = [{
+        label: strings.GetStringFromName("offlineApps.allow"),
+        accessKey: "",
+        callback: function() {
+          for (let i = 0; i < notification.documents.length; i++)
+            OfflineApps.allowSite(notification.documents[i], aTarget);
+        }
+      },{
+        label: strings.GetStringFromName("contentPermissions.neverForSite"),
+        accessKey: "",
+        callback: function() {
+          for (let i = 0; i < notification.documents.length; i++)
+            OfflineApps.disallowSite(notification.documents[i]);
+        }
+      }];
+
+      const priority = notificationBox.PRIORITY_INFO_LOW;
+      let message = strings.formatStringFromName("offlineApps.wantsTo", [host], 1);
+      notification = notificationBox.appendNotification(message, notificationID, "", priority, buttons);
+      notification.documents = [aRequest];
+    }
+  },
+
+  allowSite: function(aRequest, aTarget) {
+    let currentURI = Services.io.newURI(aRequest.location, aRequest.charset, null);
+    Services.perms.add(currentURI, "offline-app", Ci.nsIPermissionManager.ALLOW_ACTION);
+
+    // When a site is enabled while loading, manifest resources will start
+    // fetching immediately.  This one time we need to do it ourselves.
+    // The update must be started on the content process.
+    aTarget.messageManager.sendAsyncMessage("Browser:MozApplicationCache:Fetch", aRequest);
+  },
+
+  disallowSite: function(aRequest) {
+    let currentURI = Services.io.newURI(aRequest.location, aRequest.charset, null);
+    Services.perms.add(currentURI, "offline-app", Ci.nsIPermissionManager.DENY_ACTION);
+  },
+
+  receiveMessage: function receiveMessage(aMessage) {
+    if (aMessage.name == "Browser:MozApplicationManifest") {
+      this.offlineAppRequested(aMessage.json, aMessage.target);
+    }
+  }
+};
+