Replace LayoutTableCell::AbsoluteColumnIndex() with EffectiveColumnIndex()

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

Index: third_party/WebKit/Source/core/layout/LayoutTable.h
diff --git a/third_party/WebKit/Source/core/layout/LayoutTable.h b/third_party/WebKit/Source/core/layout/LayoutTable.h
index 335eea31c9ba0c8eaf6dda84c94307acaa77c089..5431633915b68cebe38eb2e77e8039c288e3a3d3 100644
--- a/third_party/WebKit/Source/core/layout/LayoutTable.h
+++ b/third_party/WebKit/Source/core/layout/LayoutTable.h
@@ -127,8 +127,8 @@ enum TableHeightChangingValue { kTableHeightNotChanging, kTableHeightChanging };
 // </table>
 //
 // Columns can be split if we add a row with a different colspan structure.
-// See splitEffectiveColumn() and appendEffectiveColumn() for operations
-// over effectiveColumns() and effectiveColumnPositions().
+// See SplitEffectiveColumn() and AppendEffectiveColumn() for operations
+// over EffectiveColumns() and EffectiveColumnPositions().
 //
 // See absoluteColumnToEffectiveColumn() for converting an absolute column
 // index into an index into effectiveColumns() and effectiveColumnPositions().
@@ -356,6 +356,7 @@ class CORE_EXPORT LayoutTable final : public LayoutBlock {
 
   // Return the first column or column-group.
   LayoutTableCol* FirstColumn() const;
+  LayoutTableCol* FirstInnermostColumn() const;
 
   struct ColAndColGroup {
     ColAndColGroup()
@@ -369,15 +370,20 @@ class CORE_EXPORT LayoutTable final : public LayoutBlock {
     bool adjoins_end_border_of_col_group;
     LayoutTableCol* InnermostColOrColGroup() { return col ? col : colgroup; }
   };
-  ColAndColGroup ColElementAtAbsoluteColumn(
-      unsigned absolute_column_index) const {
-    // The common case is to not have col/colgroup elements, make that case
-    // fast.
-    if (!has_col_elements_)
+  ColAndColGroup ColAndColGroupAtEffectiveColumn(
+      unsigned effective_column) const {
+    if (!cols_at_effective_columns_valid_)
+      UpdateColsAtEffectiveColumns();
+    if (!cols_at_effective_columns_ ||
+        effective_column >= cols_at_effective_columns_->size())
       return ColAndColGroup();
-    return SlowColElementAtAbsoluteColumn(absolute_column_index);
+    return cols_at_effective_columns_->at(effective_column);
+  }
+  bool HasColOrColGroups() const {
+    if (!cols_at_effective_columns_valid_)
+      UpdateColsAtEffectiveColumns();
+    return !!cols_at_effective_columns_;
   }
-  bool HasColElements() const { return has_col_elements_; }
 
   bool NeedsSectionRecalc() const { return needs_section_recalc_; }
   void SetNeedsSectionRecalc() {
@@ -501,10 +507,8 @@ class CORE_EXPORT LayoutTable final : public LayoutBlock {
   int FirstLineBoxBaseline() const override;
   int InlineBlockBaseline(LineDirectionMode) const override;
 
-  ColAndColGroup SlowColElementAtAbsoluteColumn(unsigned col) const;
-
-  void UpdateColumnCache() const;
-  void InvalidateCachedColumns();
+  void UpdateColsAtEffectiveColumns() const;
+  void InvalidateColsAtEffectiveColumns() const;
 
   void UpdateLogicalWidth() override;
 
@@ -557,11 +561,8 @@ class CORE_EXPORT LayoutTable final : public LayoutBlock {
   // The captions associated with this object.
   mutable Vector<LayoutTableCaption*> captions_;
 
-  // Holds pointers to LayoutTableCol objects for <col>s and <colgroup>s under
-  // this table.
-  // There is no direct relationship between the size of and index into this
-  // vector and those of m_effectiveColumns because they hold different things.
-  mutable Vector<LayoutTableCol*> column_layout_objects_;
+  // Stores cached ColAndColGroup structures at effective columns.
+  mutable std::unique_ptr<Vector<ColAndColGroup>> cols_at_effective_columns_;
 
   mutable LayoutTableSection* head_;
   mutable LayoutTableSection* foot_;
@@ -590,11 +591,10 @@ class CORE_EXPORT LayoutTable final : public LayoutBlock {
   bool collapsed_borders_valid_ : 1;
   bool needs_invalidate_collapsed_borders_for_all_cells_ : 1;
 
-  mutable bool has_col_elements_ : 1;
   mutable bool needs_section_recalc_ : 1;
 
   bool column_logical_width_changed_ : 1;
-  mutable bool column_layout_objects_valid_ : 1;
+  mutable bool cols_at_effective_columns_valid_ : 1;
   mutable unsigned no_cell_colspan_at_least_;
   unsigned CalcNoCellColspanAtLeast() const {
     for (unsigned c = 0; c < NumEffectiveColumns(); c++) {