Optimize collapsed border calculation (step 2)

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef LayoutTableBoxComponent_h
 #define LayoutTableBoxComponent_h
 
 #include "core/CoreExport.h"
 #include "core/layout/LayoutBox.h"
 #include "core/paint/PaintResult.h"
 #include "platform/graphics/paint/CullRect.h"
 
 namespace blink {
 
 class LayoutTable;
 
 // Common super class for LayoutTableCol, LayoutTableSection and LayoutTableRow.
 // Also provides utility functions for all table parts.
 class CORE_EXPORT LayoutTableBoxComponent : public LayoutBox {
  public:
-  static void InvalidateCollapsedBordersOnStyleChange(
+  static bool NeedsInvalidateCollapsedBordersOnStyleChange(

[wkorman, 2017/04/27 22:05:36]

Document this method in particular what it returns.

       const LayoutObject& table_part,
-      LayoutTable&,
+      const LayoutTable&,
       const StyleDifference&,
       const ComputedStyle& old_style);
 
   static bool DoCellsHaveDirtyWidth(const LayoutObject& table_part,
                                     const LayoutTable&,
                                     const StyleDifference&,
                                     const ComputedStyle& old_style);
 
   class MutableForPainting : public LayoutObject::MutableForPainting {
    public:
@@ skipping 37 matching lines @@
   LayoutObjectChildList children_;
 
   friend class MutableForPainting;
   PaintResult last_paint_result_;
   CullRect last_paint_rect_;
 };
 
 }  // namespace blink
 
 #endif  // LayoutTableBoxComponent_h