auto merge of #4194 : cgaebel/servo/incremental-reflow-fix, r=pcwalton

When inserting a node that was already dirtied, the dirtying logic
would short circuit: "This node is already dirty? Great! Then its
parents must be HAS_DIRTY_DESCENDANTS, too! Let's skip that step."

This isn't appropriate when nodes move around the tree. In that case,
the node may be marked HAS_CHANGED, but ancestors may not yet have
the HAS_DIRTY_DESCENDANTS flag set.

This patch adds a `content_and_heritage_changed` hook in the document,
to deal with these cases appropriately.

1 files changed, 8 insertions, 0 deletions

diff --git a/components/script/dom/document.rs b/components/script/dom/document.rs
index 174a43af664..84016cf75fa 100644
--- a/components/script/dom/document.rs
+++ b/components/script/dom/document.rs
@@ -177,6 +177,7 @@ pub trait DocumentHelpers<'a> {
     fn set_last_modified(self, value: DOMString);
     fn set_encoding_name(self, name: DOMString);
     fn content_changed(self, node: JSRef<Node>);
+    fn content_and_heritage_changed(self, node: JSRef<Node>);
     fn reflow(self);
     fn wait_until_safe_to_modify_dom(self);
     fn unregister_named_element(self, to_unregister: JSRef<Element>, id: Atom);
@@ -227,10 +228,17 @@ impl<'a> DocumentHelpers<'a> for JSRef<'a, Document> {
     }
 
     fn content_changed(self, node: JSRef<Node>) {
+        debug!("content_changed on {}", node.debug_str());
         node.dirty();
         self.reflow();
     }
 
+    fn content_and_heritage_changed(self, node: JSRef<Node>) {
+        debug!("content_and_heritage_changed on {}", node.debug_str());
+        node.force_dirty_ancestors();
+        self.reflow();
+    }
+
     fn reflow(self) {
         self.window.root().reflow();
     }