diff --git a/layout/style/test/test_media_queries.html b/layout/style/test/test_media_queries.html
index 94a4e0cd0b92..b1a62baa3fe1 100644
--- a/layout/style/test/test_media_queries.html
+++ b/layout/style/test/test_media_queries.html
@@ -27,10 +27,7 @@ SimpleTest.waitForExplicitFinish();
 var iframe;
 
 function getZoomRatio() {
-  netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
-  var utils = window.QueryInterface(Components.interfaces.nsIInterfaceRequestor)
-                    .getInterface(Components.interfaces.nsIDOMWindowUtils);
-  return utils.screenPixelsPerCSSPixel;
+  return SpecialPowers.DOMWindowUtils.screenPixelsPerCSSPixel;
 }
 
 function run() {
diff --git a/layout/style/test/test_moz_device_pixel_ratio.html b/layout/style/test/test_moz_device_pixel_ratio.html
index e27b0c6beb72..ae07230e9f81 100644
--- a/layout/style/test/test_moz_device_pixel_ratio.html
+++ b/layout/style/test/test_moz_device_pixel_ratio.html
@@ -49,10 +49,7 @@ function run() {
   }
 
   function getZoomRatio() {
-    netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
-    var utils = window.QueryInterface(Components.interfaces.nsIInterfaceRequestor)
-                      .getInterface(Components.interfaces.nsIDOMWindowUtils);
-    return utils.screenPixelsPerCSSPixel;
+    return SpecialPowers.DOMWindowUtils.screenPixelsPerCSSPixel;
   }
 
   var screenPixelsPerCSSPixel = getZoomRatio();
diff --git a/layout/style/test/test_pointer-events.html b/layout/style/test/test_pointer-events.html
index c12ddf19d2f1..893e102a0483 100644
--- a/layout/style/test/test_pointer-events.html
+++ b/layout/style/test/test_pointer-events.html
@@ -70,12 +70,8 @@ function synthesizeMouseEvent(type,                // string
                               modifiers,           // long
                               ignoreWindowBounds)  // boolean
 {
-  netscape.security.PrivilegeManager.enablePrivilege('UniversalXPConnect');
-
-  var utils = window.QueryInterface(Components.interfaces.nsIInterfaceRequestor).
-                     getInterface(Components.interfaces.nsIDOMWindowUtils);
-
-  utils.sendMouseEvent(type, x, y, button, clickCount, modifiers, ignoreWindowBounds);
+  SpecialPowers.DOMWindowUtils.sendMouseEvent(type, x, y, button, clickCount,
+                                              modifiers, ignoreWindowBounds);
 }
 
 function run_test()
diff --git a/layout/style/test/test_transitions_per_property.html b/layout/style/test/test_transitions_per_property.html
index 544e15215d67..ec1a4408177f 100644
--- a/layout/style/test/test_transitions_per_property.html
+++ b/layout/style/test/test_transitions_per_property.html
@@ -278,10 +278,8 @@ div.style.removeProperty("-moz-transition");
 
 function get_distance(prop, v1, v2)
 {
-  netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
-  var utils = window.QueryInterface(Components.interfaces.nsIInterfaceRequestor)
-                      .getInterface(Components.interfaces.nsIDOMWindowUtils);
-  return utils.computeAnimationDistance(div, prop, v1, v2);
+  return SpecialPowers.DOMWindowUtils
+           .computeAnimationDistance(div, prop, v1, v2);
 }
 
 function check_distance(prop, start, quarter, end)
diff --git a/layout/style/test/test_visited_image_loading.html b/layout/style/test/test_visited_image_loading.html
index f3d170848946..496c9730be70 100644
--- a/layout/style/test/test_visited_image_loading.html
+++ b/layout/style/test/test_visited_image_loading.html
@@ -33,10 +33,8 @@ function run()
 }
 
 function visitedDependentComputedStyle(win, elem, property) {
-  netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
-  var utils = win.QueryInterface(Components.interfaces.nsIInterfaceRequestor).
-                getInterface(Components.interfaces.nsIDOMWindowUtils);
-  return utils.getVisitedDependentComputedStyle(elem, "", property);
+  return SpecialPowers.DOMWindowUtils
+           .getVisitedDependentComputedStyle(elem, "", property);
 }
 
 function check_link_styled()
diff --git a/layout/style/test/test_visited_image_loading_empty.html b/layout/style/test/test_visited_image_loading_empty.html
index 945293dbc624..fe0de8a74d6f 100644
--- a/layout/style/test/test_visited_image_loading_empty.html
+++ b/layout/style/test/test_visited_image_loading_empty.html
@@ -33,10 +33,8 @@ function run()
 }
 
 function visitedDependentComputedStyle(win, elem, property) {
-  netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
-  var utils = win.QueryInterface(Components.interfaces.nsIInterfaceRequestor).
-                getInterface(Components.interfaces.nsIDOMWindowUtils);
-  return utils.getVisitedDependentComputedStyle(elem, "", property);
+  return SpecialPowers.DOMWindowUtils
+           .getVisitedDependentComputedStyle(elem, "", property);
 }
 
 function check_link_styled()