Implement SANACLAP (http://bit.ly/sanaclap).

third_party/WebKit/Source/core/layout/LayoutObject.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 1399 matching lines @@
         MutableForPainting(const LayoutObject& layoutObject) : m_layoutObject(const_cast<LayoutObject&>(layoutObject)) { }
 
         LayoutObject& m_layoutObject;
     };
     MutableForPainting getMutableForPainting() const { return MutableForPainting(*this); }
 
     void setIsScrollAnchorObject() { m_bitfields.setIsScrollAnchorObject(true); }
     // Clears the IsScrollAnchorObject bit, unless any ScrollAnchor still refers to us.
     void maybeClearIsScrollAnchorObject();
 
+    bool scrollAnchorDisablingStyleChanged() { return m_bitfields.scrollAnchorDisablingStyleChanged(); }
+    void setScrollAnchorDisablingStyleChanged(bool changed) { m_bitfields.setScrollAnchorDisablingStyleChanged(changed); }
+
     void clearChildNeedsOverflowRecalcAfterStyleChange() { m_bitfields.setChildNeedsOverflowRecalcAfterStyleChange(false); }
 
     bool compositedScrollsWithRespectTo(const LayoutBoxModelObject& paintInvalidationContainer) const;
     IntSize scrollAdjustmentForPaintInvalidation(const LayoutBoxModelObject& paintInvalidationContainer) const;
 
     bool previousBackgroundObscured() const { return m_bitfields.previousBackgroundObscured(); }
     void setPreviousBackgroundObscured(bool b) { m_bitfields.setPreviousBackgroundObscured(b); }
 
 protected:
     enum LayoutObjectType {
@@ skipping 301 matching lines @@
             , m_isInsideFlowThread(false)
             , m_subtreeChangeListenerRegistered(false)
             , m_notifiedOfSubtreeChange(false)
             , m_consumesSubtreeChangeNotification(false)
             , m_childrenInline(false)
             , m_containsInlineWithOutlineAndContinuation(false)
             , m_alwaysCreateLineBoxesForLayoutInline(false)
             , m_previousBackgroundObscured(false)
             , m_isBackgroundAttachmentFixedObject(false)
             , m_isScrollAnchorObject(false)
+            , m_scrollAnchorDisablingStyleChanged(false)
             , m_hasBoxDecorationBackground(false)
             , m_positionedState(IsStaticallyPositioned)
             , m_selectionState(SelectionNone)
             , m_backgroundObscurationState(BackgroundObscurationStatusInvalid)
             , m_fullPaintInvalidationReason(PaintInvalidationNone)
         {
         }
 
         // 32 bits have been used in the first word, and 18 in the second.
 
@@ skipping 118 matching lines @@
 
         // from LayoutInline
         ADD_BOOLEAN_BITFIELD(alwaysCreateLineBoxesForLayoutInline, AlwaysCreateLineBoxesForLayoutInline);
 
         // Background obscuration status of the previous frame.
         ADD_BOOLEAN_BITFIELD(previousBackgroundObscured, PreviousBackgroundObscured);
 
         ADD_BOOLEAN_BITFIELD(isBackgroundAttachmentFixedObject, IsBackgroundAttachmentFixedObject);
         ADD_BOOLEAN_BITFIELD(isScrollAnchorObject, IsScrollAnchorObject);
 
+        // Whether changes in this LayoutObject's CSS properties since the last layout should
+        // suppress any adjustments that would be made during the next layout by ScrollAnchor
+        // objects for which this LayoutObject is on the path from the anchor node to the
+        // scroller. See http://bit.ly/sanaclap for more info.
+        ADD_BOOLEAN_BITFIELD(scrollAnchorDisablingStyleChanged, ScrollAnchorDisablingStyleChanged);
+
         ADD_BOOLEAN_BITFIELD(hasBoxDecorationBackground, HasBoxDecorationBackground);
 
     private:
         // This is the cached 'position' value of this object
         // (see ComputedStyle::position).
         unsigned m_positionedState : 2; // PositionedState
         unsigned m_selectionState : 3; // SelectionState
         // Mutable for getter which lazily update this field.
         mutable unsigned m_backgroundObscurationState : 2; // BackgroundObscurationState
         unsigned m_fullPaintInvalidationReason : 5; // PaintInvalidationReason
@@ skipping 142 matching lines @@
     setSelfNeedsLayout(false);
     setPosChildNeedsLayout(false);
     setNeedsSimplifiedNormalFlowLayout(false);
     setNormalChildNeedsLayout(false);
     setNeedsPositionedMovementLayout(false);
     setAncestorLineBoxDirty(false);
 
 #if ENABLE(ASSERT)
     checkBlockPositionedObjectsNeedLayout();
 #endif
+
+    setScrollAnchorDisablingStyleChanged(false);
 }
 
 inline void LayoutObject::setChildNeedsLayout(MarkingBehavior markParents, SubtreeLayoutScope* layouter)
 {
     ASSERT(!isSetNeedsLayoutForbidden());
     bool alreadyNeededLayout = normalChildNeedsLayout();
     setNormalChildNeedsLayout(true);
     // FIXME: Replace MarkOnlyThis with the SubtreeLayoutScope code path and remove the MarkingBehavior argument entirely.
     if (!alreadyNeededLayout && markParents == MarkContainerChain && (!layouter || layouter->root() != this))
         markContainerChainForLayout(!layouter, layouter);
@@ skipping 106 matching lines @@
 void showTree(const blink::LayoutObject*);
 void showLineTree(const blink::LayoutObject*);
 void showLayoutTree(const blink::LayoutObject* object1);
 // We don't make object2 an optional parameter so that showLayoutTree
 // can be called from gdb easily.
 void showLayoutTree(const blink::LayoutObject* object1, const blink::LayoutObject* object2);
 
 #endif
 
 #endif // LayoutObject_h