Element::recalcStyle() overly reattach()-es InsertionPoints.

Source/core/dom/Node.cpp

Index: Source/core/dom/Node.cpp
diff --git a/Source/core/dom/Node.cpp b/Source/core/dom/Node.cpp
index d28320ada6db3218cecfefede5954e802ee22206..4e82e6f80fd9c7cefdf8cb7cdcff6a72bfb27580 100644
--- a/Source/core/dom/Node.cpp
+++ b/Source/core/dom/Node.cpp
@@ -835,6 +835,25 @@ inline void Node::markAncestorsWithChildNeedsStyleRecalc()
 {
     for (ContainerNode* p = parentOrShadowHostNode(); p && !p->childNeedsStyleRecalc(); p = p->parentOrShadowHostNode())
         p->setChildNeedsStyleRecalc();
+}
+
+inline void Node::markDistributionsWithNeedsStyleRecalc()
+{
+    for (ShadowRoot* root = containingShadowRoot(); root; root = root->host()->containingShadowRoot()) {
+        ScopeContentDistribution* distribution = root->scopeDistribution();
+        if (!distribution || !distribution->hasInsertionPoint(root))

[esprehn, 2013/06/13 02:25:38]

hasInsertionPoint is static, this doesn't make sense.

+            continue;
+        root->host()->setNeedsStyleRecalc();
+        const Vector<RefPtr<InsertionPoint> >& insertionPoints = distribution->ensureInsertionPointList(root);
+        for (unsigned i = 0; i < insertionPoints.size(); ++i)
+            insertionPoints[i]->setNeedsStyleRecalc();

[esprehn, 2013/06/13 02:25:38]

This is much too aggressive. Now if we setNeedsStyleRecalc a <div> in a
ShadowRoot (ex. an animation is running) we're going to cause Force style
recalcs on every ShadowRoot and all their descendants all the way down the tree.

setNeedsStyleRecalc means Force for myself and all descendants. You don't even
need this setNeedsStyleRecalc for the insertionPoints because of how big a
hammer this is.

+    }
+}
+
+inline void Node::propagateStyleRecalcMarking()
+{
+    markAncestorsWithChildNeedsStyleRecalc();
+    markDistributionsWithNeedsStyleRecalc();
 
     if (document()->childNeedsStyleRecalc())
         document()->scheduleStyleRecalc();
@@ -861,7 +880,7 @@ void Node::setNeedsStyleRecalc(StyleChangeType changeType)
         setStyleChange(changeType);
 
     if (existingChangeType == NoStyleChange)
-        markAncestorsWithChildNeedsStyleRecalc();
+        propagateStyleRecalcMarking();
 }
 
 void Node::lazyAttach()
@@ -877,7 +896,7 @@ void Node::lazyAttach()
         return;
     }
     setStyleChange(FullStyleChange);
-    markAncestorsWithChildNeedsStyleRecalc();
+    propagateStyleRecalcMarking();
 }
 
 bool Node::supportsFocus() const