Check modified event state from layout and dirty it there.

This adds some overhead, but also provides the small performance benefit of
avoiding dirtying in the case where an event state is toggled an even
number of times between reflows.

The main benefit here though is that it sets us up to be smarter about
what we mark as dirty using restyle hints.

1 files changed, 2 insertions, 10 deletions

diff --git a/components/script/dom/window.rs b/components/script/dom/window.rs
index 761ede6edf8..abe693696fd 100644
--- a/components/script/dom/window.rs
+++ b/components/script/dom/window.rs
@@ -957,16 +957,8 @@ impl Window {
     ///
     /// TODO(pcwalton): Only wait for style recalc, since we have off-main-thread layout.
     pub fn reflow(&self, goal: ReflowGoal, query_type: ReflowQueryType, reason: ReflowReason) {
-        let document = self.Document();
-        let root = document.r().GetDocumentElement();
-        let root = match root.r() {
-            Some(root) => root,
-            None => return,
-        };
-
-        let root = root.upcast::<Node>();
-        if query_type == ReflowQueryType::NoQuery && !root.get_has_dirty_descendants() {
-            debug!("root has no dirty descendants; avoiding reflow (reason {:?})", reason);
+        if query_type == ReflowQueryType::NoQuery && !self.Document().needs_reflow() {
+            debug!("Document doesn't need reflow - skipping it (reason {:?})", reason);
             return
         }