diff -r 000000000000 -r 6474c204b198 browser/devtools/styleinspector/test/browser_styleinspector_csslogic-content-stylesheets.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/styleinspector/test/browser_styleinspector_csslogic-content-stylesheets.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,72 @@
+/* vim: set ft=javascript ts=2 et sw=2 tw=80: */
+/* Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Check stylesheets on HMTL and XUL document
+
+const TEST_URI_HTML = TEST_URL_ROOT + "doc_content_stylesheet.html";
+const TEST_URI_XUL = TEST_URL_ROOT + "doc_content_stylesheet.xul";
+const XUL_URI = Cc["@mozilla.org/network/io-service;1"]
+                .getService(Ci.nsIIOService)
+                .newURI(TEST_URI_XUL, null, null);
+const XUL_PRINCIPAL = Components.classes["@mozilla.org/scriptsecuritymanager;1"]
+                        .getService(Ci.nsIScriptSecurityManager)
+                        .getNoAppCodebasePrincipal(XUL_URI);
+
+let {CssLogic} = devtools.require("devtools/styleinspector/css-logic");
+
+let test = asyncTest(function*() {
+  info("Checking stylesheets on HTML document");
+  yield addTab(TEST_URI_HTML);
+  let target = getNode("#target");
+
+  let {toolbox, inspector, view} = yield openRuleView();
+  yield selectNode(target, inspector);
+
+  info("Checking stylesheets");
+  checkSheets(target);
+
+  info("Checking stylesheets on XUL document");
+  info("Allowing XUL content");
+  allowXUL();
+  yield addTab(TEST_URI_XUL);
+
+  let {toolbox, inspector, view} = yield openRuleView();
+  let target = getNode("#target");
+  yield selectNode(target, inspector);
+
+  checkSheets(target);
+  info("Disallowing XUL content");
+  disallowXUL();
+});
+
+function allowXUL() {
+  Cc["@mozilla.org/permissionmanager;1"].getService(Ci.nsIPermissionManager)
+    .addFromPrincipal(XUL_PRINCIPAL, 'allowXULXBL', Ci.nsIPermissionManager.ALLOW_ACTION);
+}
+
+function disallowXUL() {
+  Cc["@mozilla.org/permissionmanager;1"].getService(Ci.nsIPermissionManager)
+    .addFromPrincipal(XUL_PRINCIPAL, 'allowXULXBL', Ci.nsIPermissionManager.DENY_ACTION);
+}
+
+function checkSheets(target) {
+  let domUtils = Cc["@mozilla.org/inspector/dom-utils;1"]
+      .getService(Ci.inIDOMUtils);
+  let domRules = domUtils.getCSSStyleRules(target);
+
+  for (let i = 0, n = domRules.Count(); i < n; i++) {
+    let domRule = domRules.GetElementAt(i);
+    let sheet = domRule.parentStyleSheet;
+    let isContentSheet = CssLogic.isContentStylesheet(sheet);
+
+    if (!sheet.href ||
+        /doc_content_stylesheet_/.test(sheet.href)) {
+      ok(isContentSheet, sheet.href + " identified as content stylesheet");
+    } else {
+      ok(!isContentSheet, sheet.href + " identified as non-content stylesheet");
+    }
+  }
+}