Optimize collapsed border calculation (step 1)

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

 /*
  * Copyright (C) 1997 Martin Jones (mjones@kde.org)
  *           (C) 1997 Torben Weis (weis@kde.org)
  *           (C) 1998 Waldo Bastian (bastian@kde.org)
  *           (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2013 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  *
@@ skipping 39 matching lines @@
 namespace blink {
 
 using namespace HTMLNames;
 
 LayoutTable::LayoutTable(Element* element)
     : LayoutBlock(element),
       head_(nullptr),
       foot_(nullptr),
       first_body_(nullptr),
       collapsed_borders_valid_(false),
+      needs_invalidate_collapsed_borders_for_all_cells_(false),
       has_col_elements_(false),
       needs_section_recalc_(false),
       column_logical_width_changed_(false),
       column_layout_objects_valid_(false),
       no_cell_colspan_at_least_(0),
       h_spacing_(0),
       v_spacing_(0),
       border_start_(0),
       border_end_(0) {
   DCHECK(!ChildrenInline());
@@ skipping 700 matching lines @@
   // to update the value as its used by flexbox layout. crbug.com/367324
   SetIntrinsicContentLogicalHeight(ContentLogicalHeight());
 
   column_logical_width_changed_ = false;
   ClearNeedsLayout();
 }
 
 void LayoutTable::InvalidateCollapsedBorders() {
   collapsed_borders_.clear();
   collapsed_borders_valid_ = false;
+  needs_invalidate_collapsed_borders_for_all_cells_ = true;
   SetMayNeedPaintInvalidation();
 }
 
+void LayoutTable::InvalidateCollapsedBordersForAllCellsIfNeeded() {
+  DCHECK(CollapseBorders());
+
+  if (!needs_invalidate_collapsed_borders_for_all_cells_)
+    return;
+  needs_invalidate_collapsed_borders_for_all_cells_ = false;
+
+  for (LayoutObject* section = FirstChild(); section;
+       section = section->NextSibling()) {
+    if (!section->IsTableSection())
+      continue;
+    for (LayoutTableRow* row = ToLayoutTableSection(section)->FirstRow(); row;
+         row = row->NextRow()) {
+      for (LayoutTableCell* cell = row->FirstCell(); cell;
+           cell = cell->NextCell()) {
+        DCHECK_EQ(cell->Table(), this);
+        cell->InvalidateCollapsedBorderValues();
+      }
+    }
+  }
+}
+
 // Collect all the unique border values that we want to paint in a sorted list.
 // During the collection, each cell saves its recalculated borders into the
 // cache of its containing section, and invalidates itself if any border
 // changes. This method doesn't affect layout.
 void LayoutTable::RecalcCollapsedBordersIfNeeded() {
   if (collapsed_borders_valid_ || !CollapseBorders())
     return;
   collapsed_borders_valid_ = true;
   collapsed_borders_.clear();
   for (LayoutObject* section = FirstChild(); section;
@@ skipping 942 matching lines @@
 }
 
 LayoutUnit LayoutTable::PaddingRight() const {
   if (CollapseBorders())
     return LayoutUnit();
 
   return LayoutBlock::PaddingRight();
 }
 
 }  // namespace blink