diff -r 000000000000 -r 6474c204b198 browser/modules/ContentLinkHandler.jsm
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/modules/ContentLinkHandler.jsm	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,141 @@
+/* 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/. */
+
+"use strict";
+
+let Cc = Components.classes;
+let Ci = Components.interfaces;
+let Cu = Components.utils;
+
+this.EXPORTED_SYMBOLS = [ "ContentLinkHandler" ];
+
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+Cu.import("resource://gre/modules/Services.jsm");
+
+XPCOMUtils.defineLazyModuleGetter(this, "Feeds",
+  "resource:///modules/Feeds.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "BrowserUtils",
+  "resource://gre/modules/BrowserUtils.jsm");
+
+this.ContentLinkHandler = {
+  init: function(chromeGlobal) {
+    chromeGlobal.addEventListener("DOMLinkAdded", (event) => {
+      this.onLinkAdded(event, chromeGlobal);
+    }, false);
+  },
+
+  onLinkAdded: function(event, chromeGlobal) {
+    var link = event.originalTarget;
+    var rel = link.rel && link.rel.toLowerCase();
+    if (!link || !link.ownerDocument || !rel || !link.href)
+      return;
+
+    // Ignore sub-frames (bugs 305472, 479408).
+    let window = link.ownerDocument.defaultView;
+    if (window != window.top)
+      return;
+
+    var feedAdded = false;
+    var iconAdded = false;
+    var searchAdded = false;
+    var rels = {};
+    for (let relString of rel.split(/\s+/))
+      rels[relString] = true;
+
+    for (let relVal in rels) {
+      switch (relVal) {
+        case "feed":
+        case "alternate":
+          if (!feedAdded) {
+            if (!rels.feed && rels.alternate && rels.stylesheet)
+              break;
+
+            if (Feeds.isValidFeed(link, link.ownerDocument.nodePrincipal, "feed" in rels)) {
+              chromeGlobal.sendAsyncMessage("Link:AddFeed",
+                                            {type: link.type,
+                                             href: link.href,
+                                             title: link.title});
+              feedAdded = true;
+            }
+          }
+          break;
+        case "icon":
+          if (!iconAdded) {
+            if (!Services.prefs.getBoolPref("browser.chrome.site_icons"))
+              break;
+
+            var uri = this.getLinkIconURI(link);
+            if (!uri)
+              break;
+
+            [iconAdded] = chromeGlobal.sendSyncMessage("Link:AddIcon", {url: uri.spec});
+          }
+          break;
+        case "search":
+          if (!searchAdded) {
+            var type = link.type && link.type.toLowerCase();
+            type = type.replace(/^\s+|\s*(?:;.*)?$/g, "");
+
+            let re = /^(?:https?|ftp):/i;
+            if (type == "application/opensearchdescription+xml" && link.title &&
+                re.test(link.href))
+            {
+              let engine = { title: link.title, href: link.href };
+              chromeGlobal.sendAsyncMessage("Link:AddSearch",
+                                            {engine: engine,
+                                             url: link.ownerDocument.documentURI});
+              searchAdded = true;
+            }
+          }
+          break;
+      }
+    }
+  },
+
+  getLinkIconURI: function(aLink) {
+    let targetDoc = aLink.ownerDocument;
+    var uri = BrowserUtils.makeURI(aLink.href, targetDoc.characterSet);
+
+    // Verify that the load of this icon is legal.
+    // Some error or special pages can load their favicon.
+    // To be on the safe side, only allow chrome:// favicons.
+    var isAllowedPage = [
+      /^about:neterror\?/,
+      /^about:blocked\?/,
+      /^about:certerror\?/,
+      /^about:home$/,
+    ].some(function (re) re.test(targetDoc.documentURI));
+
+    if (!isAllowedPage || !uri.schemeIs("chrome")) {
+      var ssm = Services.scriptSecurityManager;
+      try {
+        ssm.checkLoadURIWithPrincipal(targetDoc.nodePrincipal, uri,
+                                      Ci.nsIScriptSecurityManager.DISALLOW_SCRIPT);
+      } catch(e) {
+        return null;
+      }
+    }
+
+    try {
+      var contentPolicy = Cc["@mozilla.org/layout/content-policy;1"].
+                          getService(Ci.nsIContentPolicy);
+    } catch(e) {
+      return null; // Refuse to load if we can't do a security check.
+    }
+
+    // Security says okay, now ask content policy
+    if (contentPolicy.shouldLoad(Ci.nsIContentPolicy.TYPE_IMAGE,
+                                 uri, targetDoc.documentURIObject,
+                                 aLink, aLink.type, null)
+                                 != Ci.nsIContentPolicy.ACCEPT)
+      return null;
+
+    try {
+      uri.userPass = "";
+    } catch(e) {
+      // some URIs are immutable
+    }
+    return uri;
+  },
+};