Fix Border collapsing with colpsan / rowspan cells

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

Index: third_party/WebKit/Source/core/layout/LayoutTableCol.h
diff --git a/third_party/WebKit/Source/core/layout/LayoutTableCol.h b/third_party/WebKit/Source/core/layout/LayoutTableCol.h
index c9c54ed6c52d3bc9c024c9c90076d2e450db8a67..251672d5df19ad9f8c304f375740180fca53bbb2 100644
--- a/third_party/WebKit/Source/core/layout/LayoutTableCol.h
+++ b/third_party/WebKit/Source/core/layout/LayoutTableCol.h
@@ -67,7 +67,7 @@ class LayoutTableCol final : public LayoutTableBoxComponent {
   // For CSS table columns or colgroups, this is always 1.
   unsigned Span() const { return span_; }
 
-  bool IsTableColumnGroupWithColumnChildren() { return FirstChild(); }
+  bool IsTableColumnGroupWithColumnChildren() const { return FirstChild(); }
   bool IsTableColumn() const {
     return Style()->Display() == EDisplay::kTableColumn;
   }
@@ -76,6 +76,7 @@ class LayoutTableCol final : public LayoutTableBoxComponent {
   }
 
   LayoutTableCol* EnclosingColumnGroup() const;
+  LayoutTableCol* LastColumnInGroup() const;
 
   // Returns the next column or column-group.
   LayoutTableCol* NextColumn() const;
@@ -88,6 +89,12 @@ class LayoutTableCol final : public LayoutTableBoxComponent {
 
   const char* GetName() const override { return "LayoutTableCol"; }
 
+  // Return indexes to all columns inside this element.
+  // Can return vector with size 0 if LayoutTableCol is out of range.
+  // <col> element can return size() > 2 if it spans multiple columns
+  // <colgroup> element can return any size.
+  Vector<unsigned> GetEffectiveColumnIndexes() const;
+
  private:
   bool IsOfType(LayoutObjectType type) const override {
     return type == kLayoutObjectLayoutTableCol || LayoutBox::IsOfType(type);