Skip traversing wholeSubtree subtrees with clean invalidation bits.

Source/core/css/invalidation/StyleInvalidator.cpp

 
 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 
 #include "core/css/invalidation/StyleInvalidator.h"
 
 #include "core/css/invalidation/DescendantInvalidationSet.h"
@@ skipping 122 matching lines @@
     return someChildrenNeedStyleRecalc;
 }
 
 bool StyleInvalidator::invalidate(Element& element)
 {
     RecursionCheckpoint checkpoint(&m_recursionData);
 
     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) {
         element.setNeedsStyleRecalc(m_recursionData.wholeSubtreeInvalid() ? SubtreeStyleChange : LocalStyleChange);
     } else if (m_recursionData.hasInvalidationSets() && someChildrenNeedStyleRecalc) {
         // Clone the RenderStyle in order to preserve correct style sharing, if possible. Otherwise recalc style.
         if (RenderObject* renderer = element.renderer())
             renderer->setStyleInternal(RenderStyle::clone(renderer->style()));
         else
             element.setNeedsStyleRecalc(LocalStyleChange);
     }
 
     element.clearChildNeedsStyleInvalidation();
     element.clearNeedsStyleInvalidation();
 
     return thisElementNeedsStyleRecalc;
 }
 
 void StyleInvalidator::trace(Visitor* visitor)
 {
     visitor->trace(m_pendingInvalidationMap);
 }
 
 } // namespace WebCore