Add early out back to Node::updateDistribution().

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 6cb9f35f4a68f03d5a4fde44829c03c71e8df83c..1a14679ed6db74c334cbea4e649086733500dc87 100644
--- a/Source/core/dom/Node.cpp
+++ b/Source/core/dom/Node.cpp
@@ -653,13 +653,20 @@ bool Node::needsDistributionRecalc() const
 
 void Node::updateDistribution()
 {
+    // Extra early out to avoid spamming traces.
+    if (inDocument() && !document().childNeedsDistributionRecalc())
+        return;
     TRACE_EVENT0("blink", "Node::updateDistribution");
     ScriptForbiddenScope forbidScript;
-    rootInTreeOfTrees(*this).recalcDistribution();
+    Node& root = rootInTreeOfTrees(*this);
+    if (root.childNeedsDistributionRecalc())
+        root.recalcDistribution();
 }
 
 void Node::recalcDistribution()
 {
+    ASSERT(childNeedsDistributionRecalc());
+
     if (isElementNode()) {
         if (ElementShadow* shadow = toElement(this)->shadow())
             shadow->distributeIfNeeded();