Statistics of LayoutBox rare data reasons

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2006, 2007 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.
  *
@@ skipping 91 matching lines @@
     return *m_snapAreas;
   }
 
   // Used by BoxPaintInvalidator. Stores the previous content box size and
   // layout overflow rect after the last paint invalidation. They are valid if
   // m_hasPreviousContentBoxSizeAndLayoutOverflowRect is true.
   LayoutSize m_previousContentBoxSize;
   LayoutRect m_previousLayoutOverflowRect;
 };
 
+CORE_EXPORT int* rareDataReasonCounts();
+
 // LayoutBox implements the full CSS box model.
 //
 // LayoutBoxModelObject only introduces some abstractions for LayoutInline and
 // LayoutBox. The logic for the model is in LayoutBox, e.g. the storage for the
 // rectangle and offset forming the CSS box (m_frameRect) and the getters for
 // the different boxes.
 //
 // LayoutBox is also the uppermost class to support scrollbars, however the
 // logic is delegated to PaintLayerScrollableArea.
 // Per the CSS specification, scrollbars should "be inserted between the inner
@@ skipping 69 matching lines @@
 // MR = margin-right
 // PL = padding-left
 // PR = padding-right
 // SC = scroll corner (contains UI for resizing (see the 'resize' property)
 // SW = scrollbar width
 //
 // Those are just the boxes from the CSS model. Extra boxes are tracked by Blink
 // (e.g. the overflows). Thus it is paramount to know which box a function is
 // manipulating. Also of critical importance is the coordinate system used (see
 // the COORDINATE SYSTEMS section in LayoutBoxModelObject).
+
 class CORE_EXPORT LayoutBox : public LayoutBoxModelObject {
  public:
   explicit LayoutBox(ContainerNode*);
 
   PaintLayerType layerTypeRequired() const override;
 
   bool backgroundIsKnownToBeOpaqueInRect(
       const LayoutRect& localRect) const override;
 
   virtual bool backgroundShouldAlwaysBeClipped() const { return false; }
@@ skipping 1337 matching lines @@
   //
   // See INTRINSIC SIZES / PREFERRED LOGICAL WIDTHS in LayoutObject.h for more
   // details about those widths.
   virtual void computePreferredLogicalWidths() {
     clearPreferredLogicalWidthsDirty();
   }
 
   LayoutBoxRareData& ensureRareData() {
     if (!m_rareData)
       m_rareData = WTF::makeUnique<LayoutBoxRareData>();
+    m_rareStat.addReason(ReasonLBRareData);
     return *m_rareData.get();
   }
 
   bool logicalHeightComputesAsNone(SizeType) const;
 
   bool isBox() const =
       delete;  // This will catch anyone doing an unnecessary check.
 
   void locationChanged();
   void sizeChanged();
@@ skipping 119 matching lines @@
     // m_inlineBoxWrapper should already be nullptr. Deleting it is a safeguard
     // against security issues. Otherwise, there will two line box wrappers
     // keeping the reference to this layoutObject, and only one will be notified
     // when the layoutObject is getting destroyed. The second line box wrapper
     // will keep a stale reference.
     if (UNLIKELY(m_inlineBoxWrapper != nullptr))
       deleteLineBoxWrapper();
   }
 
   m_inlineBoxWrapper = boxWrapper;
+  if (boxWrapper)
+    m_rareStat.addReason(ReasonLBInlineBoxWrapper);
 }
 
 inline bool LayoutBox::isForcedFragmentainerBreakValue(
     EBreakBetween breakValue) {
   return breakValue == EBreakBetween::kColumn ||
          breakValue == EBreakBetween::kLeft ||
          breakValue == EBreakBetween::kPage ||
          breakValue == EBreakBetween::kRecto ||
          breakValue == EBreakBetween::kRight ||
          breakValue == EBreakBetween::kVerso;
 }
 
 }  // namespace blink
 
 #endif  // LayoutBox_h