Recalc sibling styles for forward positional rules on mutations only.

Source/core/dom/ElementRareData.h

 /*
  * Copyright (C) 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2008 David Smith <catfish.man@gmail.com>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 66 matching lines @@
     void setChildrenAffectedByActive(bool value) { m_childrenAffectedByActive = value; }
     bool childrenAffectedByDrag() const { return m_childrenAffectedByDrag; }
     void setChildrenAffectedByDrag(bool value) { m_childrenAffectedByDrag = value; }
 
     bool childrenAffectedByFirstChildRules() const { return m_childrenAffectedByFirstChildRules; }
     void setChildrenAffectedByFirstChildRules(bool value) { m_childrenAffectedByFirstChildRules = value; }
     bool childrenAffectedByLastChildRules() const { return m_childrenAffectedByLastChildRules; }
     void setChildrenAffectedByLastChildRules(bool value) { m_childrenAffectedByLastChildRules = value; }
     bool childrenAffectedByDirectAdjacentRules() const { return m_childrenAffectedByDirectAdjacentRules; }
     void setChildrenAffectedByDirectAdjacentRules(bool value) { m_childrenAffectedByDirectAdjacentRules = value; }
+    bool childrenAffectedByIndirectAdjacentRules() const { return m_childrenAffectedByIndirectAdjacentRules; }
+    void setChildrenAffectedByIndirectAdjacentRules(bool value) { m_childrenAffectedByIndirectAdjacentRules = value; }
     bool childrenAffectedByForwardPositionalRules() const { return m_childrenAffectedByForwardPositionalRules; }
     void setChildrenAffectedByForwardPositionalRules(bool value) { m_childrenAffectedByForwardPositionalRules = value; }
     bool childrenAffectedByBackwardPositionalRules() const { return m_childrenAffectedByBackwardPositionalRules; }
     void setChildrenAffectedByBackwardPositionalRules(bool value) { m_childrenAffectedByBackwardPositionalRules = value; }
     unsigned childIndex() const { return m_childIndex; }
     void setChildIndex(unsigned index) { m_childIndex = index; }
 
     CSSStyleDeclaration& ensureInlineCSSStyleDeclaration(Element* ownerElement);
 
     void clearShadow() { m_shadow = nullptr; }
@@ skipping 63 matching lines @@
     unsigned m_childrenAffectedByFocus : 1;
     unsigned m_childrenAffectedByHover : 1;
     unsigned m_childrenAffectedByActive : 1;
     unsigned m_childrenAffectedByDrag : 1;
     // Bits for dynamic child matching.
     // We optimize for :first-child and :last-child. The other positional child selectors like nth-child or
     // *-child-of-type, we will just give up and re-evaluate whenever children change at all.
     unsigned m_childrenAffectedByFirstChildRules : 1;
     unsigned m_childrenAffectedByLastChildRules : 1;
     unsigned m_childrenAffectedByDirectAdjacentRules : 1;
+    unsigned m_childrenAffectedByIndirectAdjacentRules : 1;
     unsigned m_childrenAffectedByForwardPositionalRules : 1;
     unsigned m_childrenAffectedByBackwardPositionalRules : 1;
 
     LayoutSize m_minimumSizeForResizing;
     IntSize m_savedLayerScrollOffset;
     RefPtr<RenderStyle> m_computedStyle;
 
     OwnPtr<DatasetDOMStringMap> m_dataset;
     OwnPtr<ClassList> m_classList;
     OwnPtr<ElementShadow> m_shadow;
@@ skipping 25 matching lines @@
     , m_containsFullScreenElement(false)
     , m_isInTopLayer(false)
     , m_hasPendingResources(false)
     , m_childrenAffectedByFocus(false)
     , m_childrenAffectedByHover(false)
     , m_childrenAffectedByActive(false)
     , m_childrenAffectedByDrag(false)
     , m_childrenAffectedByFirstChildRules(false)
     , m_childrenAffectedByLastChildRules(false)
     , m_childrenAffectedByDirectAdjacentRules(false)
+    , m_childrenAffectedByIndirectAdjacentRules(false)
     , m_childrenAffectedByForwardPositionalRules(false)
     , m_childrenAffectedByBackwardPositionalRules(false)
     , m_minimumSizeForResizing(defaultMinimumSizeForResizing())
 {
 }
 
 inline ElementRareData::~ElementRareData()
 {
     ASSERT(!m_shadow);
     ASSERT(!m_generatedBefore);
@@ skipping 58 matching lines @@
 
 inline void ElementRareData::resetDynamicRestyleObservations()
 {
     setChildrenAffectedByFocus(false);
     setChildrenAffectedByHover(false);
     setChildrenAffectedByActive(false);
     setChildrenAffectedByDrag(false);
     setChildrenAffectedByFirstChildRules(false);
     setChildrenAffectedByLastChildRules(false);
     setChildrenAffectedByDirectAdjacentRules(false);
+    setChildrenAffectedByIndirectAdjacentRules(false);
     setChildrenAffectedByForwardPositionalRules(false);
     setChildrenAffectedByBackwardPositionalRules(false);
 }
 
 } // namespace
 
 #endif // ElementRareData_h