Statistics of LayoutBox rare data reasons

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

Index: third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp b/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
index 34394d9fefa93349d81016ebb644b680f17f947e..ef8626b3c40d7e45661b705fa02867c03c5ac480 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
@@ -250,6 +250,7 @@ LayoutBlockFlow::LayoutBlockFlow(ContainerNode* node) : LayoutBlock(node) {
   static_assert(sizeof(MarginInfo) == sizeof(SameSizeAsMarginInfo),
                 "MarginInfo should stay small");
   setChildrenInline(true);
+  m_rareStat.addReason(ReasonLBFAll);
 }
 
 LayoutBlockFlow::~LayoutBlockFlow() {}
@@ -286,6 +287,7 @@ void LayoutBlockFlow::setBreakAtLineToAvoidWidow(int lineToBreak) {
   ensureRareData();
   ASSERT(!m_rareData->m_didBreakAtLineToAvoidWidow);
   m_rareData->m_lineBreakToAvoidWidow = lineToBreak;
+  m_rareStat.addReason(ReasonLBFLineBreakToAvoidWidow);
 }
 
 void LayoutBlockFlow::setDidBreakAtLineToAvoidWidow() {
@@ -2229,6 +2231,9 @@ void LayoutBlockFlow::setMustDiscardMarginBefore(bool value) {
     m_rareData = WTF::makeUnique<LayoutBlockFlowRareData>(this);
 
   m_rareData->m_discardMarginBefore = value;
+
+  if (value)
+    m_rareStat.addReason(ReasonLBFDiscardMargin);
 }
 
 void LayoutBlockFlow::setMustDiscardMarginAfter(bool value) {
@@ -2244,6 +2249,9 @@ void LayoutBlockFlow::setMustDiscardMarginAfter(bool value) {
     m_rareData = WTF::makeUnique<LayoutBlockFlowRareData>(this);
 
   m_rareData->m_discardMarginAfter = value;
+
+  if (value)
+    m_rareStat.addReason(ReasonLBFDiscardMargin);
 }
 
 bool LayoutBlockFlow::mustDiscardMarginBefore() const {
@@ -2304,6 +2312,7 @@ void LayoutBlockFlow::setMaxMarginBeforeValues(LayoutUnit pos, LayoutUnit neg) {
   }
   m_rareData->m_margins.setPositiveMarginBefore(pos);
   m_rareData->m_margins.setNegativeMarginBefore(neg);
+  m_rareStat.addReason(ReasonLBFMargin);
 }
 
 void LayoutBlockFlow::setMaxMarginAfterValues(LayoutUnit pos, LayoutUnit neg) {
@@ -2315,6 +2324,7 @@ void LayoutBlockFlow::setMaxMarginAfterValues(LayoutUnit pos, LayoutUnit neg) {
   }
   m_rareData->m_margins.setPositiveMarginAfter(pos);
   m_rareData->m_margins.setNegativeMarginAfter(neg);
+  m_rareStat.addReason(ReasonLBFMargin);
 }
 
 bool LayoutBlockFlow::mustSeparateMarginBeforeForChild(
@@ -4137,6 +4147,7 @@ void LayoutBlockFlow::setPaginationStrutPropagatedFromChild(LayoutUnit strut) {
     m_rareData = WTF::makeUnique<LayoutBlockFlowRareData>(this);
   }
   m_rareData->m_paginationStrutPropagatedFromChild = strut;
+  m_rareStat.addReason(ReasonLBFPaginationStrutFromChild);
 }
 
 void LayoutBlockFlow::setFirstForcedBreakOffset(LayoutUnit blockOffset) {
@@ -4299,6 +4310,7 @@ void LayoutBlockFlow::createOrDestroyMultiColumnFlowThreadIfNeeded(
   LayoutBlockFlowRareData& rareData = ensureRareData();
   ASSERT(!rareData.m_multiColumnFlowThread);
   rareData.m_multiColumnFlowThread = flowThread;
+  m_rareStat.addReason(ReasonLBFMultiColumnFlowThread);
 }
 
 LayoutBlockFlow::LayoutBlockFlowRareData& LayoutBlockFlow::ensureRareData() {