Skip traversing wholeSubtree subtrees with clean invalidation bits.

Source/core/css/invalidation/StyleInvalidator.cpp

Index: Source/core/css/invalidation/StyleInvalidator.cpp
diff --git a/Source/core/css/invalidation/StyleInvalidator.cpp b/Source/core/css/invalidation/StyleInvalidator.cpp
index 3874c2b93e68f63610c8ad2889e925bec1a61e84..5f93cc5579f26a863bf30ff386e955a6011986fd 100644
--- a/Source/core/css/invalidation/StyleInvalidator.cpp
+++ b/Source/core/css/invalidation/StyleInvalidator.cpp
@@ -140,7 +140,7 @@ bool StyleInvalidator::invalidate(Element& element)
     bool thisElementNeedsStyleRecalc = checkInvalidationSetsAgainstElement(element);
 
     bool someChildrenNeedStyleRecalc = false;
-    if (m_recursionData.hasInvalidationSets() || element.childNeedsStyleInvalidation())
+    if ((!m_recursionData.wholeSubtreeInvalid() && m_recursionData.hasInvalidationSets()) || element.childNeedsStyleInvalidation())

[esprehn, 2014/06/05 09:40:24]

I think we should just return false from hasInvalidationSets() here. There's no
sets to invalidate if the whole subtree is invalid.

[rune, 2014/06/05 09:52:26]

Done.

         someChildrenNeedStyleRecalc = invalidateChildren(element);
 
     if (thisElementNeedsStyleRecalc) {