Statistics of LayoutBox rare data reasons

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

Index: third_party/WebKit/Source/core/layout/LayoutBox.h
diff --git a/third_party/WebKit/Source/core/layout/LayoutBox.h b/third_party/WebKit/Source/core/layout/LayoutBox.h
index aca950dfdaef5226338fab9bb65e51c04b10e851..6f633aa628e0315c378b70d36a6ec68d51caf142 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBox.h
+++ b/third_party/WebKit/Source/core/layout/LayoutBox.h
@@ -109,6 +109,8 @@ struct LayoutBoxRareData {
   LayoutRect m_previousLayoutOverflowRect;
 };
 
+CORE_EXPORT int* rareDataReasonCounts();
+
 // LayoutBox implements the full CSS box model.
 //
 // LayoutBoxModelObject only introduces some abstractions for LayoutInline and
@@ -198,6 +200,7 @@ struct LayoutBoxRareData {
 // (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*);
@@ -1555,6 +1558,7 @@ class CORE_EXPORT LayoutBox : public LayoutBoxModelObject {
   LayoutBoxRareData& ensureRareData() {
     if (!m_rareData)
       m_rareData = WTF::makeUnique<LayoutBoxRareData>();
+    m_rareStat.addReason(ReasonLBRareData);
     return *m_rareData.get();
   }
 
@@ -1694,6 +1698,8 @@ inline void LayoutBox::setInlineBoxWrapper(InlineBox* boxWrapper) {
   }
 
   m_inlineBoxWrapper = boxWrapper;
+  if (boxWrapper)
+    m_rareStat.addReason(ReasonLBInlineBoxWrapper);
 }
 
 inline bool LayoutBox::isForcedFragmentainerBreakValue(