RLSA needsLayout on customscrollbar thickness change.

Source/core/rendering/RenderBox.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2006, 2007 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 432 matching lines @@
     // Block flows subclass availableWidth/Height to handle multi column layout (shrinking the width/height available to children when laying out.)
     virtual LayoutUnit availableLogicalWidth() const { return contentLogicalWidth(); }
     virtual LayoutUnit availableLogicalHeight(AvailableLogicalHeightType) const;
     LayoutUnit availableLogicalHeightUsing(const Length&, AvailableLogicalHeightType) const;
 
     // There are a few cases where we need to refer specifically to the available physical width and available physical height.
     // Relative positioning is one of those cases, since left/top offsets are physical.
     LayoutUnit availableWidth() const { return style()->isHorizontalWritingMode() ? availableLogicalWidth() : availableLogicalHeight(IncludeMarginBorderPadding); }
     LayoutUnit availableHeight() const { return style()->isHorizontalWritingMode() ? availableLogicalHeight(IncludeMarginBorderPadding) : availableLogicalWidth(); }
 
+    void setCustomScrollbarThicknessChanged(bool thicknessChanged) { m_customScrollbarThicknessChanged = thicknessChanged; }

[skobes, 2014/11/14 03:32:10]

Instead of adding a new boolean, can you put this method in RenderBlock and have
it set m_widthAvailableToChildrenChanged directly?  Also I would suggest calling
it notifyScrollbarThicknessChanged.

You can downcast at the call site, e.g.

if (box->isRenderBlock())
  toRenderBlock(box)->notifyScrollbarThicknessChanged();

I don't think any other subclass of RenderBox would be affected by this.

[MuVen, 2014/11/14 06:10:25]

Done.

+    bool customScrollbarThicknessChanged() const { return m_customScrollbarThicknessChanged; }
+
     virtual int verticalScrollbarWidth() const;
     int horizontalScrollbarHeight() const;
     int instrinsicScrollbarLogicalWidth() const;
     int scrollbarLogicalHeight() const { return style()->isHorizontalWritingMode() ? horizontalScrollbarHeight() : verticalScrollbarWidth(); }
     virtual bool scroll(ScrollDirection, ScrollGranularity, float delta = 1);
     bool canBeScrolledAndHasScrollableArea() const;
     virtual bool canBeProgramaticallyScrolled() const;
     virtual void autoscroll(const IntPoint&);
     bool canAutoscroll() const;
     IntSize calculateAutoscrollDirection(const IntPoint& windowPoint) const;
@@ skipping 295 matching lines @@
     LayoutUnit m_minPreferredLogicalWidth;
 
     // The preferred logical width of the element if it never breaks any lines at all.
     LayoutUnit m_maxPreferredLogicalWidth;
 
     // Our overflow information.
     OwnPtr<RenderOverflow> m_overflow;
 
 private:
     OwnPtr<RenderBoxRareData> m_rareData;
+
+    unsigned m_customScrollbarThicknessChanged : 1;
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderBox, isBox());
 
 inline RenderBox* RenderBox::previousSiblingBox() const
 {
     return toRenderBox(previousSibling());
 }
 
 inline RenderBox* RenderBox::nextSiblingBox() const
@@ skipping 27 matching lines @@
         if (UNLIKELY(inlineBoxWrapper() != 0))
             deleteLineBoxWrapper();
     }
 
     ensureRareData().m_inlineBoxWrapper = boxWrapper;
 }
 
 } // namespace blink
 
 #endif // RenderBox_h