Offset repeating theads correctly when two tables adjoin at a page border

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

Index: third_party/WebKit/Source/core/layout/LayoutTableSection.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutTableSection.cpp b/third_party/WebKit/Source/core/layout/LayoutTableSection.cpp
index 63675b82dfaed5d8d5dcafd8c010353eaa3f441c..8d978bbb47e05f882d46f9f152199b6ff0c01a21 100644
--- a/third_party/WebKit/Source/core/layout/LayoutTableSection.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutTableSection.cpp
@@ -1125,6 +1125,7 @@ void LayoutTableSection::layoutRows()
 
 int LayoutTableSection::paginationStrutForRow(LayoutTableRow* row, LayoutUnit logicalOffset) const
 {
+    DCHECK(row);
     // Even if the row allows us to break-inside, we will want to put a strut on the row if we have a header
     // group that wants to appear at the top of each page.
     bool tableHeaderForcesStrut = table()->header() ? table()->header()->getPaginationBreakability() != AllowAnyBreaks : false;