[css-tables] Don't use internal layout structure when iterating all rows

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

Index: third_party/WebKit/Source/core/layout/LayoutTableSection.h
diff --git a/third_party/WebKit/Source/core/layout/LayoutTableSection.h b/third_party/WebKit/Source/core/layout/LayoutTableSection.h
index edd70aa94dd431b05e4201e72e21ae17eb172a98..fc25e9224ebcbd21e48f64d5b3898ab285a7077c 100644
--- a/third_party/WebKit/Source/core/layout/LayoutTableSection.h
+++ b/third_party/WebKit/Source/core/layout/LayoutTableSection.h
@@ -246,7 +246,11 @@ public:
     int outerBorderStart() const { return m_outerBorderStart; }
     int outerBorderEnd() const { return m_outerBorderEnd; }
 
-    unsigned numRows() const { return m_grid.size(); }
+    unsigned numRows() const
+    {
+        DCHECK(!needsCellRecalc());
+        return m_grid.size();
+    }
     unsigned numEffectiveColumns() const;
 
     // recalcCells() is used when we are not sure about the section's structure