Do-not-commit: Count layout tree memory usage

third_party/WebKit/Source/core/paint/PaintLayer.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights
  * reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
@@ skipping 193 matching lines @@
 }
 
 String PaintLayer::debugName() const {
   return layoutObject().debugName();
 }
 
 LayoutRect PaintLayer::visualRect() const {
   return m_layoutObject.visualRect();
 }
 
+char PaintLayer::approximateHeapMemoryUsage() const {
+  int memory = 0;
+  if (m_ancestorDependentCompositingInputs)
+    memory += sizeof(AncestorDependentCompositingInputs);
+  if (m_scrollableArea) {
+    // TODO(pdr): Include the additional heap allocations in
+    // PaintLayerScrollableArea.
+    memory += sizeof(PaintLayerScrollableArea);
+  }
+  if (m_ancestorDependentCompositingInputs)
+    memory += sizeof(AncestorDependentCompositingInputs);
+  if (m_clipRectsCache)
+    memory += sizeof(ClipRectsCache);
+  if (m_stackingNode)
+    memory += sizeof(PaintLayerStackingNode);
+  if (m_previousPaintingClipRects)
+    memory += sizeof(ClipRects);
+  if (m_rareData)
+    memory += sizeof(PaintLayerRareData);
+  return memory;
+}
+
 PaintLayerCompositor* PaintLayer::compositor() const {
   if (!layoutObject().view())
     return 0;
   return layoutObject().view()->compositor();
 }
 
 void PaintLayer::contentChanged(ContentChangeType changeType) {
   // updateLayerCompositingState will query compositingReasons for accelerated
   // overflow scrolling.  This is tripped by
   // LayoutTests/compositing/content-changed-chicken-egg.html
@@ skipping 3026 matching lines @@
 }
 
 void showLayerTree(const blink::LayoutObject* layoutObject) {
   if (!layoutObject) {
     LOG(INFO) << "Cannot showLayerTree. Root is (nil)";
     return;
   }
   showLayerTree(layoutObject->enclosingLayer());
 }
 #endif