diff --git a/components/layout/layout_task.rs b/components/layout/layout_task.rs
index 87f34ce2a8c..da3b7518f3f 100644
--- a/components/layout/layout_task.rs
+++ b/components/layout/layout_task.rs
@@ -954,9 +954,6 @@ impl LayoutTask {
             node.dump();
         }
 
-        let stylesheets: Vec<&Stylesheet> = data.document_stylesheets.iter().map(|entry| &**entry)
-                                                                            .collect();
-        let stylesheets_changed = data.stylesheets_changed;
         let initial_viewport = data.window_size.initial_viewport;
         let old_viewport_size = self.viewport_size;
         let current_screen_size = Size2D::new(Au::from_f32_px(initial_viewport.width.get()),
@@ -964,7 +961,7 @@ impl LayoutTask {
 
         // Calculate the actual viewport as per DEVICE-ADAPT § 6
         let device = Device::new(MediaType::Screen, initial_viewport);
-        rw_data.stylist.set_device(device, &stylesheets);
+        rw_data.stylist.set_device(device, &data.document_stylesheets);
 
         let constraints = rw_data.stylist.viewport_constraints().clone();
         self.viewport_size = match constraints {
@@ -990,7 +987,8 @@ impl LayoutTask {
         }
 
         // If the entire flow tree is invalid, then it will be reflowed anyhow.
-        let needs_dirtying = rw_data.stylist.update(&stylesheets, stylesheets_changed);
+        let needs_dirtying = rw_data.stylist.update(&data.document_stylesheets,
+                                                    data.stylesheets_changed);
         let needs_reflow = viewport_size_changed && !needs_dirtying;
         unsafe {
             if needs_dirtying {
diff --git a/components/style/selector_matching.rs b/components/style/selector_matching.rs
index dd99a3f26b4..a2fd14ff249 100644
--- a/components/style/selector_matching.rs
+++ b/components/style/selector_matching.rs
@@ -18,6 +18,7 @@ use selectors::parser::PseudoElement;
 use selectors::states::*;
 use smallvec::VecLike;
 use std::process;
+use std::sync::Arc;
 use style_traits::viewport::ViewportConstraints;
 use stylesheets::{CSSRuleIteratorExt, Origin, Stylesheet};
 use url::Url;
@@ -141,7 +142,7 @@ impl Stylist {
         stylist
     }
 
-    pub fn update(&mut self, doc_stylesheets: &[&Stylesheet],
+    pub fn update(&mut self, doc_stylesheets: &[Arc<Stylesheet>],
                       stylesheets_changed: bool) -> bool {
         if !(self.is_device_dirty || stylesheets_changed) {
             return false;
@@ -239,7 +240,7 @@ impl Stylist {
         self.state_deps.compute_hint(element, snapshot, current_state)
     }
 
-    pub fn set_device(&mut self, mut device: Device, stylesheets: &[&Stylesheet]) {
+    pub fn set_device(&mut self, mut device: Device, stylesheets: &[Arc<Stylesheet>]) {
         let cascaded_rule = stylesheets.iter()
             .flat_map(|s| s.effective_rules(&self.device).viewport())
             .cascade();