Statistics of LayoutBox rare data reasons

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

Index: third_party/WebKit/Source/core/layout/LayoutObject.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutObject.cpp b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
index e0ce2763815212db5fd5cbbc3ee6b5bf4cf95dff..2f73f09c97af5433dac6bf5c4f4a609fb0e3f9ea 100644
--- a/third_party/WebKit/Source/core/layout/LayoutObject.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
@@ -101,6 +101,12 @@ static bool gModifyLayoutTreeStructureAnyState = false;
 
 }  // namespace
 
+int RareDataStat::s_reasonCounts[MaxReason] = {0};
+
+int* rareDataReasonCounts() {
+  return RareDataStat::s_reasonCounts;
+}
+
 #if DCHECK_IS_ON()
 
 LayoutObject::SetLayoutNeededForbiddenScope::SetLayoutNeededForbiddenScope(
@@ -129,8 +135,8 @@ struct SameSizeAsLayoutObject : DisplayItemClient {
   std::unique_ptr<void*> m_paintProperties;
 };
 
-static_assert(sizeof(LayoutObject) == sizeof(SameSizeAsLayoutObject),
-              "LayoutObject should stay small");
+// static_assert(sizeof(LayoutObject) == sizeof(SameSizeAsLayoutObject),
+// "LayoutObject should stay small");
 
 bool LayoutObject::s_affectsParentBlock = false;
 
@@ -232,6 +238,8 @@ LayoutObject::LayoutObject(Node* node)
   InstanceCounters::incrementCounter(InstanceCounters::LayoutObjectCounter);
   if (m_node)
     frameView()->incrementLayoutObjectCount();
+
+  m_rareStat.addReason(ReasonLOAll);
 }
 
 LayoutObject::~LayoutObject() {
@@ -1210,6 +1218,18 @@ PaintInvalidationReason LayoutObject::invalidatePaintIfNeeded(
 
   setVisualRect(newVisualRect);
   paintInvalidator.setLocationInBacking(context.newLocation);
+  if (!newVisualRect.isEmpty() &&
+      newVisualRect.location() != context.newLocation) {
+    m_rareStat.addReason(ReasonLocationOffsetObject);
+    if (isBox())
+      m_rareStat.addReason(ReasonLocationOffsetBox);
+    if (isText())
+      m_rareStat.addReason(ReasonLocationOffsetText);
+    if (isLayoutInline())
+      m_rareStat.addReason(ReasonLocationOffsetInline);
+    if (isSVG())
+      m_rareStat.addReason(ReasonLocationOffsetSVG);
+  }
 
   if (!shouldCheckForPaintInvalidation() &&
       paintInvalidationState