Implement the overflow-anchor CSS property as an opt-out for ScrollAnchoring

third_party/WebKit/Source/core/style/ComputedStyle.cpp

 /*
  * Copyright (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2011 Adobe Systems Incorporated. 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
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 276 matching lines @@
     m_box = other.m_box;
     m_visual = other.m_visual;
     m_background = other.m_background;
     m_surround = other.m_surround;
     m_rareNonInheritedData = other.m_rareNonInheritedData;
 
     // The flags are copied one-by-one because m_nonInheritedData.m_contains a bunch of stuff other than real style data.
     // See comments for each skipped flag below.
     m_nonInheritedData.m_effectiveDisplay = other.m_nonInheritedData.m_effectiveDisplay;
     m_nonInheritedData.m_originalDisplay = other.m_nonInheritedData.m_originalDisplay;
+    m_nonInheritedData.m_overflowAnchor = other.m_nonInheritedData.m_overflowAnchor;
     m_nonInheritedData.m_overflowX = other.m_nonInheritedData.m_overflowX;
     m_nonInheritedData.m_overflowY = other.m_nonInheritedData.m_overflowY;
     m_nonInheritedData.m_verticalAlign = other.m_nonInheritedData.m_verticalAlign;
     m_nonInheritedData.m_clear = other.m_nonInheritedData.m_clear;
     m_nonInheritedData.m_position = other.m_nonInheritedData.m_position;
     m_nonInheritedData.m_floating = other.m_nonInheritedData.m_floating;
     m_nonInheritedData.m_tableLayout = other.m_nonInheritedData.m_tableLayout;
     m_nonInheritedData.m_unicodeBidi = other.m_nonInheritedData.m_unicodeBidi;
     m_nonInheritedData.m_hasViewportUnits = other.m_nonInheritedData.m_hasViewportUnits;
     m_nonInheritedData.m_breakBefore = other.m_nonInheritedData.m_breakBefore;
@@ skipping 1627 matching lines @@
         if (value < 0)
             fvalue -= 0.5f;
         else
             fvalue += 0.5f;
     }
 
     return roundForImpreciseConversion<int>(fvalue / zoomFactor);
 }
 
 } // namespace blink