Statistics of LayoutBox rare data reasons

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

Index: third_party/WebKit/Source/core/layout/LayoutTableCell.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutTableCell.cpp b/third_party/WebKit/Source/core/layout/LayoutTableCell.cpp
index f10f6cedcf210fca9c0f990dd5e8dff9d81ee92b..a5f0298eddf5b339b068d106d53b7d47eb966969 100644
--- a/third_party/WebKit/Source/core/layout/LayoutTableCell.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutTableCell.cpp
@@ -66,6 +66,7 @@ LayoutTableCell::LayoutTableCell(Element* element)
   // colSpanOrRowSpanChanged() so we need to set their initial values here in
   // case something asks for colSpan()/rowSpan() before then.
   updateColAndRowSpanFlags();
+  m_rareStat.addReason(ReasonLTCAll);
 }
 
 LayoutTableCell::CollapsedBorderValues::CollapsedBorderValues(
@@ -1371,6 +1372,13 @@ void LayoutTableCell::collectBorderValues(
   addBorderStyle(borderValues, newValues.endBorder());
   addBorderStyle(borderValues, newValues.beforeBorder());
   addBorderStyle(borderValues, newValues.afterBorder());
+
+  m_rareStat.addReason(ReasonLTCCollapsedBorders);
+  if (!newValues.startBorder().isVisible() &&
+      !newValues.endBorder().isVisible() &&
+      !newValues.beforeBorder().isVisible() &&
+      !newValues.afterBorder().isVisible())
+    m_rareStat.addReason(ReasonLTCInvisibleCollapsedBorders);
 }
 
 void LayoutTableCell::sortBorderValues(