Intersection Observer first draft

Source/core/layout/LayoutView.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple 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
  * 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 994 matching lines @@
     float scale = m_frameView ? m_frameView->frame().pageZoomFactor() : 1;
     return viewHeight(IncludeScrollbars) / scale;
 }
 
 void LayoutView::willBeDestroyed()
 {
     LayoutBlockFlow::willBeDestroyed();
     m_compositor.clear();
 }
 
+void LayoutView::addIntersectionObserverTarget(LayoutObject* obj)
+{
+    m_intersectionObserverTargets.add(obj, IntRect());
+}
+
+void LayoutView::removeIntersectionObserverTarget(LayoutObject* obj)
+{
+    m_intersectionObserverTargets.remove(obj);
+}
+
 } // namespace blink