Do-not-commit: Count layout tree memory usage

third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 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 242 matching lines @@
           frameView->removeViewportConstrainedObject(*this);
       }
     }
   }
 
   LayoutObject::willBeDestroyed();
 
   destroyLayer();
 }
 
+char LayoutBoxModelObject::approximateHeapMemoryUsage() const {
+  int memory = LayoutObject::approximateHeapMemoryUsage();
+  if (m_layer) {
+    memory += sizeof(PaintLayer);
+    memory += m_layer->approximateHeapMemoryUsage();
+  }
+  if (m_rareData)
+    memory += sizeof(LayoutBoxModelObjectRareData);
+  return memory;
+}
+
 void LayoutBoxModelObject::styleWillChange(StyleDifference diff,
                                            const ComputedStyle& newStyle) {
   // This object's layer may begin or cease to be a stacking context, in which
   // case the paint invalidation container of this object and descendants may
   // change. Thus we need to invalidate paint eagerly for all such children.
   // PaintLayerCompositor::paintInvalidationOnCompositingChange() doesn't work
   // for the case because we can only see the new paintInvalidationContainer
   // during compositing update.
   if (style() &&
       (style()->isStackingContext() != newStyle.isStackingContext())) {
@@ skipping 1195 matching lines @@
   if (rootElementStyle->hasBackground())
     return false;
 
   if (node() != document().firstBodyElement())
     return false;
 
   return true;
 }
 
 }  // namespace blink