style: Stop refcounting the stylist.

components/layout_thread/lib.rs

@@ -133,7 +133,7 @@ pub struct LayoutThread {
     url: ServoUrl,
 
     /// Performs CSS selector matching and style resolution.
-    stylist: ::StyleArc<Stylist>,
+    stylist: Stylist,
 
     /// Is the current reflow of an iframe, as opposed to a root window?
     is_iframe: bool,
@@ -418,7 +418,7 @@ impl LayoutThread {
         let font_cache_receiver =
             ROUTER.route_ipc_receiver_to_new_mpsc_receiver(ipc_font_cache_receiver);
 
-        let stylist = StyleArc::new(Stylist::new(device));
+        let stylist = Stylist::new(device);
         let outstanding_web_fonts_counter = Arc::new(AtomicUsize::new(0));
         let ua_stylesheets = &*UA_STYLESHEETS;
         let guard = ua_stylesheets.shared_lock.read();
@@ -679,11 +679,10 @@ impl LayoutThread {
             size: display_list.map_or(0, |sc| sc.heap_size_of_children()),
         });
 
-        let stylist = self.stylist.as_ref();
         reports.push(Report {
             path: path![formatted_url, "layout-thread", "stylist"],
             kind: ReportKind::ExplicitJemallocHeapSize,
-            size: stylist.heap_size_of_children(),
+            size: self.stylist.heap_size_of_children(),
         });
 
         // The LayoutThread has data in Persistent TLS...
@@ -780,7 +779,7 @@ impl LayoutThread {
 
     /// Sets quirks mode for the document, causing the quirks mode stylesheet to be used.
     fn handle_set_quirks_mode<'a, 'b>(&mut self, quirks_mode: QuirksMode) {
-        StyleArc::get_mut(&mut self.stylist).unwrap().set_quirks_mode(quirks_mode);
+        self.stylist.set_quirks_mode(quirks_mode);
     }
 
     fn try_get_layout_root<N: LayoutNode>(&self, node: N) -> Option<FlowRef> {
@@ -1038,8 +1037,7 @@ impl LayoutThread {
         self.document_shared_lock = Some(document_shared_lock.clone());
         let author_guard = document_shared_lock.read();
         let device = Device::new(MediaType::Screen, initial_viewport);
-        StyleArc::get_mut(&mut self.stylist).unwrap()
+        self.stylist.set_device(device, &author_guard, &data.document_stylesheets);
-            .set_device(device, &author_guard, &data.document_stylesheets);
 
         self.viewport_size =
             self.stylist.viewport_constraints().map_or(current_screen_size, |constraints| {
@@ -1092,7 +1090,7 @@ impl LayoutThread {
         let mut extra_data = ExtraStyleData {
             marker: PhantomData,
         };
-        let needs_dirtying = StyleArc::get_mut(&mut self.stylist).unwrap().update(
+        let needs_dirtying = self.stylist.update(
             &data.document_stylesheets,
             &guards,
             Some(ua_stylesheets),

components/style/gecko/data.rs

@@ -25,7 +25,7 @@ use stylist::{ExtraStyleData, Stylist};
 /// itself.
 pub struct PerDocumentStyleDataImpl {
     /// Rule processor.
-    pub stylist: Arc<Stylist>,
+    pub stylist: Stylist,
 
     /// List of stylesheets, mirrored from Gecko.
     pub stylesheets: StylesheetSet,
@@ -60,7 +60,7 @@ impl PerDocumentStyleData {
         let (new_anims_sender, new_anims_receiver) = channel();
 
         PerDocumentStyleData(AtomicRefCell::new(PerDocumentStyleDataImpl {
-            stylist: Arc::new(Stylist::new(device)),
+            stylist: Stylist::new(device),
             stylesheets: StylesheetSet::new(),
             new_animations_sender: new_anims_sender,
             new_animations_receiver: new_anims_receiver,
@@ -86,10 +86,7 @@ impl PerDocumentStyleDataImpl {
     ///
     /// Implies also a stylesheet flush.
     pub fn reset_device(&mut self, guard: &SharedRwLockReadGuard) {
-        {
+        Arc::get_mut(&mut self.stylist.device).unwrap().reset();
-            let mut stylist = Arc::get_mut(&mut self.stylist).unwrap();
-            Arc::get_mut(&mut stylist.device).unwrap().reset();
-        }
         self.stylesheets.force_dirty();
         self.flush_stylesheets(guard);
     }
@@ -100,7 +97,6 @@ impl PerDocumentStyleDataImpl {
             return;
         }
 
-        let mut stylist = Arc::get_mut(&mut self.stylist).unwrap();
         let mut extra_data = ExtraStyleData {
             font_faces: &mut self.font_faces,
         };
@@ -108,13 +104,13 @@ impl PerDocumentStyleDataImpl {
         let author_style_disabled = self.stylesheets.author_style_disabled();
         let mut stylesheets = Vec::<Arc<Stylesheet>>::new();
         self.stylesheets.flush(&mut stylesheets);
-        stylist.clear();
+        self.stylist.clear();
-        stylist.rebuild(stylesheets.as_slice(),
+        self.stylist.rebuild(stylesheets.as_slice(),
-                        &StylesheetGuards::same(guard),
+                             &StylesheetGuards::same(guard),
-                        /* ua_sheets = */ None,
+                             /* ua_sheets = */ None,
-                        /* stylesheets_changed = */ true,
+                             /* stylesheets_changed = */ true,
-                        author_style_disabled,
+                             author_style_disabled,
-                        &mut extra_data);
+                             &mut extra_data);
     }
 
     /// Get the default computed values for this document.
@@ -125,8 +121,7 @@ impl PerDocumentStyleDataImpl {
     /// Clear the stylist.  This will be a no-op if the stylist is
     /// already cleared; the stylist handles that.
     pub fn clear_stylist(&mut self) {
-        let mut stylist = Arc::get_mut(&mut self.stylist).unwrap();
+        self.stylist.clear();
-        stylist.clear();
     }
 }