Do-not-commit: Count layout tree memory usage

third_party/WebKit/Source/core/layout/LayoutFlexibleBox.h

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 29 matching lines @@
 class FlexItem;
 
 class CORE_EXPORT LayoutFlexibleBox : public LayoutBlock {
  public:
   LayoutFlexibleBox(Element*);
   ~LayoutFlexibleBox() override;
 
   static LayoutFlexibleBox* createAnonymous(Document*);
 
   const char* name() const override { return "LayoutFlexibleBox"; }
+  char objectSize() const override { return sizeof(this); }
+  char approximateHeapMemoryUsage() const override {
+    int memory = LayoutBlock::approximateHeapMemoryUsage();
+    // TODO(pdr): Include memory from m_intrinsicSizeAlongMainAxis.
+    // TODO(pdr): Include memory from m_relaidOutChildren
+    return memory;
+  }
 
   bool isFlexibleBox() const final { return true; }
   void layoutBlock(bool relayoutChildren) final;
 
   int baselinePosition(
       FontBaseline,
       bool firstLine,
       LineDirectionMode,
       LinePositionMode = PositionOnContainingLine) const override;
   int firstLineBoxBaseline() const override;
@@ skipping 192 matching lines @@
   // This is SizeIsUnknown outside of layoutBlock()
   mutable SizeDefiniteness m_hasDefiniteHeight;
   bool m_inLayout;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutFlexibleBox, isFlexibleBox());
 
 }  // namespace blink
 
 #endif  // LayoutFlexibleBox_h