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

third_party/WebKit/Source/core/css/CSSComputedStyleDeclaration.cpp

 /*
  * Copyright (C) 2004 Zack Rusin <zack@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
  * Copyright (C) 2011 Sencha, Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
@@ skipping 128 matching lines @@
     CSSPropertyMotionPath,
     CSSPropertyMotionRotation,
     CSSPropertyObjectFit,
     CSSPropertyObjectPosition,
     CSSPropertyOpacity,
     CSSPropertyOrphans,
     CSSPropertyOutlineColor,
     CSSPropertyOutlineOffset,
     CSSPropertyOutlineStyle,
     CSSPropertyOutlineWidth,
+    CSSPropertyOverflowAnchor,
     CSSPropertyOverflowWrap,
     CSSPropertyOverflowX,
     CSSPropertyOverflowY,
     CSSPropertyPaddingBottom,
     CSSPropertyPaddingLeft,
     CSSPropertyPaddingRight,
     CSSPropertyPaddingTop,
     CSSPropertyPointerEvents,
     CSSPropertyPosition,
     CSSPropertyResize,
@@ skipping 540 matching lines @@
     exceptionState.throwDOMException(NoModificationAllowedError, "These styles are computed, and therefore the '" + getPropertyNameString(id) + "' property is read-only.");
 }
 
 DEFINE_TRACE(CSSComputedStyleDeclaration)
 {
     visitor->trace(m_node);
     CSSStyleDeclaration::trace(visitor);
 }
 
 } // namespace blink