Statistics of LayoutBox rare data reasons

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

Index: third_party/WebKit/Source/core/layout/LayoutTable.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutTable.cpp b/third_party/WebKit/Source/core/layout/LayoutTable.cpp
index a60abf0d658c3524fd18737bcf3cf481e0eadc19..1c6297ce3429a051ecf04359246583528ec256e6 100644
--- a/third_party/WebKit/Source/core/layout/LayoutTable.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutTable.cpp
@@ -1673,6 +1673,59 @@ const BorderValue& LayoutTable::tableEndBorderAdjoiningCell(
 void LayoutTable::ensureIsReadyForPaintInvalidation() {
   LayoutBlock::ensureIsReadyForPaintInvalidation();
   recalcCollapsedBordersIfNeeded();
+
+  bool hasColBackground = false;
+  for (LayoutTableCol* col = firstColumn(); col; col = col->nextColumn()) {
+    if (col->styleRef().hasBackground()) {
+      hasColBackground = true;
+      break;
+    }
+  }
+
+  for (LayoutObject* child = firstChild(); child;
+       child = child->nextSibling()) {
+    if (!child->isTableSection())
+      continue;
+    LayoutTableSection* section = toLayoutTableSection(child);
+    if (section->isPaintInvalidationContainer()) {
+      section->m_rareStat.addReason(ReasonLTSComposited);
+      if (hasColBackground) {
+        section->m_rareStat.addReason(
+            ReasonLTSCompositedWithContainerBackground);
+      }
+    } else {
+      section->m_rareStat.addReason(ReasonLTSNonComposited);
+    }
+    bool hasSectionBackground = section->styleRef().hasBackground();
+    for (LayoutTableRow* row = section->firstRow(); row; row = row->nextRow()) {
+      if (row->isPaintInvalidationContainer()) {
+        row->m_rareStat.addReason(ReasonLTRComposited);
+        if (hasSectionBackground || hasColBackground)
+          row->m_rareStat.addReason(ReasonLTRCompositedWithContainerBackground);
+      } else {
+        row->m_rareStat.addReason(ReasonLTRNonComposited);
+      }
+      bool hasRowBackground = row->styleRef().hasBackground();
+      for (LayoutTableCell* cell = row->firstCell(); cell;
+           cell = cell->nextCell()) {
+        if (cell->isPaintInvalidationContainer()) {
+          cell->m_rareStat.addReason(ReasonLTCComposited);
+          ColAndColGroup colAndColGroup =
+              colElementAtAbsoluteColumn(cell->absoluteColumnIndex());
+          LayoutTableCol* column = colAndColGroup.col;
+          LayoutTableCol* columnGroup = colAndColGroup.colgroup;
+          if ((column && column->styleRef().hasBackground()) ||
+              (columnGroup && columnGroup->styleRef().hasBackground()) ||
+              hasSectionBackground || hasRowBackground) {
+            cell->m_rareStat.addReason(
+                ReasonLTCCompositedWithContainerBackground);
+          }
+        } else {
+          cell->m_rareStat.addReason(ReasonLTCNonComposited);
+        }
+      }
+    }
+  }
 }
 
 PaintInvalidationReason LayoutTable::invalidatePaintIfNeeded(