Fix Border collapsing with colpsan / rowspan cells

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 4d51fd471ce1d2449701fd4520d515a0bf20faf0..9e87f5c81f82d3964c752db35479a93ba84d280e 100644
--- a/third_party/WebKit/Source/core/layout/LayoutTable.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutTable.cpp
@@ -964,6 +964,13 @@ LayoutTableSection* LayoutTable::TopNonEmptySection() const {
   return section;
 }
 
+LayoutTableSection* LayoutTable::BottomNonEmptySection() const {
+  LayoutTableSection* section = BottomSection();
+  if (section && !section->NumRows())
+    section = SectionAbove(section, kSkipEmptySections);
+  return section;
+}
+
 void LayoutTable::SplitEffectiveColumn(unsigned index, unsigned first_span) {
   // We split the column at |index|, taking |firstSpan| cells from the span.
   DCHECK_GT(effective_columns_[index].span, first_span);
@@ -1083,6 +1090,25 @@ LayoutTable::ColAndColGroup LayoutTable::SlowColElementAtAbsoluteColumn(
   return ColAndColGroup();
 }
 
+// Maps LayoutTableCol => absoluteColumnIndex,
+// an inverse of slowColElementAtAbsoluteColumn
+unsigned LayoutTable::ColElementToAbsoluteColumn(
+    const LayoutTableCol* col_element) const {
+  unsigned col = 0;
+  for (LayoutTableCol* column_layout_object = FirstColumn();
+       column_layout_object;
+       column_layout_object = column_layout_object->NextColumn()) {
+    if (column_layout_object == col_element)
+      break;
+    if (column_layout_object->IsTableColumnGroupWithColumnChildren()) {
+      // Do nothing, span will increase with children
+    } else {
+      col += column_layout_object->Span();
+    }
+  }
+  return col;
+}
+
 void LayoutTable::RecalcSections() const {
   DCHECK(needs_section_recalc_);