[css-tables] Set needsLayout on cells when column border width changes

third_party/WebKit/Source/core/layout/LayoutTableCol.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, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 32 matching lines @@
     updateFromElement();
 }
 
 void LayoutTableCol::styleDidChange(StyleDifference diff, const ComputedStyle* oldStyle)
 {
     LayoutTableBoxComponent::styleDidChange(diff, oldStyle);
 
     if (LayoutTable* table = this->table()) {
         if (!oldStyle)
             return;
+
+        // TODO(dgrogan): Is the "else" necessary for correctness or just a brittle optimization? The optimization would be:
+        // if the first branch is taken then the next one can't be, so don't even check its condition.
         if (!table->selfNeedsLayout() && !table->normalChildNeedsLayout() && oldStyle->border() != style()->border()) {
             // If border was changed, notify table.
             table->invalidateCollapsedBorders();
-        } else if (oldStyle->logicalWidth() != style()->logicalWidth()) {
-            // FIXME : setPreferredLogicalWidthsDirty is done for all cells as of now.
-            // Need to find a better way so that only the cells which are changed by
-            // the col width should have preferred logical widths recomputed.
+        } else if ((oldStyle->logicalWidth() != style()->logicalWidth()) || (diff.needsFullLayout() && needsLayout() && table->collapseBorders() && oldStyle->border().sizeEquals(style()->border()))) {
+            // TODO(dgrogan): Move second clause above to LayoutTableBoxComponent for re-use.
+            // TODO(dgrogan): Optimization opportunities:
+            // (1) Only mark cells which are affected by this col, not every cell in the table.
+            // (2) If only the col width changes and its border width doesn't, do the cells need to be marked as
+            //     needing layout or just given dirty widths?
             for (LayoutObject* child = table->children()->firstChild(); child; child = child->nextSibling()) {
                 if (!child->isTableSection())
                     continue;
                 LayoutTableSection* section = toLayoutTableSection(child);
-                for (LayoutTableRow* row = section->firstRow(); row; row = row->nextRow()) {
-                    for (LayoutTableCell* cell = row->firstCell(); cell; cell = cell->nextCell())
-                        cell->setPreferredLogicalWidthsDirty();
-                }
+                section->markAllCellsWidthsDirtyAndOrNeedsLayout(LayoutTableSection::MarkDirtyAndNeedsLayout);
             }
         }
     }
 }
 
 void LayoutTableCol::updateFromElement()
 {
     unsigned oldSpan = m_span;
     Node* n = node();
     if (isHTMLTableColElement(n)) {
@@ skipping 109 matching lines @@
     return style()->borderStart();
 }
 
 const BorderValue& LayoutTableCol::borderAdjoiningCellAfter(const LayoutTableCell* cell) const
 {
     ASSERT_UNUSED(cell, table()->colElementAtAbsoluteColumn(cell->absoluteColumnIndex() - 1).innermostColOrColGroup() == this);
     return style()->borderEnd();
 }
 
 } // namespace blink