[New Multicolumn] Let a spanner's containing block be the multicol container.

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 12 matching lines @@
 #ifndef RenderBox_h
 #define RenderBox_h
 
 #include "core/rendering/RenderBoxModelObject.h"
 #include "core/rendering/RenderOverflow.h"
 #include "core/rendering/shapes/ShapeOutsideInfo.h"
 #include "platform/scroll/ScrollTypes.h"
 
 namespace blink {
 
+class RenderMultiColumnSpannerPlaceholder;
+
 struct PaintInfo;
 
 enum SizeType { MainOrPreferredSize, MinSize, MaxSize };
 enum AvailableLogicalHeightType { ExcludeMarginBorderPadding, IncludeMarginBorderPadding };
 enum OverlayScrollbarSizeRelevancy { IgnoreOverlayScrollbarSize, IncludeOverlayScrollbarSize };
 enum MarginDirection { BlockDirection, InlineDirection };
 
 enum ShouldComputePreferred { ComputeActual, ComputePreferred };
 
 enum ScrollOffsetClamping {
     ScrollOffsetUnclamped,
     ScrollOffsetClamped
 };
 
 struct RenderBoxRareData {
     WTF_MAKE_NONCOPYABLE(RenderBoxRareData); WTF_MAKE_FAST_ALLOCATED;
 public:
     RenderBoxRareData()
         : m_inlineBoxWrapper(0)
+        , m_spannerPlaceholder(0)
         , m_overrideLogicalContentHeight(-1)
         , m_overrideLogicalContentWidth(-1)
         , m_previousBorderBoxSize(-1, -1)
     {
     }
 
     // For inline replaced elements, the inline box that owns us.
     InlineBox* m_inlineBoxWrapper;
 
+    // For spanners, the spanner placeholder that lays us out within the multicol container.
+    RenderMultiColumnSpannerPlaceholder* m_spannerPlaceholder;
+
     LayoutUnit m_overrideLogicalContentHeight;
     LayoutUnit m_overrideLogicalContentWidth;
 
     // Set by RenderBox::updatePreviousBorderBoxSizeIfNeeded().
     LayoutSize m_previousBorderBoxSize;
 };
 
 class RenderBox : public RenderBoxModelObject {
 public:
     explicit RenderBox(ContainerNode*);
@@ skipping 318 matching lines @@
     virtual InlineBox* createInlineBox();
     void dirtyLineBoxes(bool fullLayout);
 
     // For inline replaced elements, this function returns the inline box that owns us.  Enables
     // the replaced RenderObject to quickly determine what line it is contained on and to easily
     // iterate over structures on the line.
     InlineBox* inlineBoxWrapper() const { return m_rareData ? m_rareData->m_inlineBoxWrapper : 0; }
     void setInlineBoxWrapper(InlineBox*);
     void deleteLineBoxWrapper();
 
+    void setSpannerPlaceholder(RenderMultiColumnSpannerPlaceholder*);
+    virtual RenderMultiColumnSpannerPlaceholder* spannerPlaceholder() const override final { return m_rareData ? m_rareData->m_spannerPlaceholder : 0; }

[Julien - ping for review, 2014/12/11 19:09:37]

We just put final per
https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/sjotlpNyF-8

[mstensho (USE GERRIT), 2014/12/11 21:01:14]

Done.

+
     virtual LayoutRect clippedOverflowRectForPaintInvalidation(const RenderLayerModelObject* paintInvalidationContainer, const PaintInvalidationState* = 0) const override;
     virtual void mapRectToPaintInvalidationBacking(const RenderLayerModelObject* paintInvalidationContainer, LayoutRect&, const PaintInvalidationState*) const override;
     virtual void invalidatePaintForOverhangingFloats(bool paintAllDescendants);
 
     virtual LayoutUnit containingBlockLogicalWidthForContent() const override;
     LayoutUnit containingBlockLogicalHeightForContent(AvailableLogicalHeightType) const;
 
     LayoutUnit containingBlockAvailableLineWidth() const;
     LayoutUnit perpendicularContainingBlockLogicalHeight() const;
 
@@ skipping 237 matching lines @@
     void markShapeOutsideDependentsForLayout()
     {
         if (isFloating())
             removeFloatingOrPositionedChildFromBlockLists();
     }
 
     bool backgroundHasOpaqueTopLayer() const;
 
     void setIntrinsicContentLogicalHeight(LayoutUnit intrinsicContentLogicalHeight) const { m_intrinsicContentLogicalHeight = intrinsicContentLogicalHeight; }
 protected:
+    virtual void willBeRemovedFromTree() override;
     virtual void willBeDestroyed() override;
 
-
     virtual void styleWillChange(StyleDifference, const RenderStyle& newStyle) override;
     virtual void styleDidChange(StyleDifference, const RenderStyle* oldStyle) override;
     virtual void updateFromStyle() override;
 
     // Returns false if it could not cheaply compute the extent (e.g. fixed background), in which case the returned rect may be incorrect.
     // FIXME: make this a const method once the RenderBox reference in BoxPainter is const.
     bool getBackgroundPaintedExtent(LayoutRect&);
     virtual bool foregroundIsKnownToBeOpaqueInRect(const LayoutRect& localRect, unsigned maxDepthToTest) const;
     virtual bool computeBackgroundIsKnownToBeObscured() override;
 
@@ skipping 144 matching lines @@
         if (UNLIKELY(inlineBoxWrapper() != 0))
             deleteLineBoxWrapper();
     }
 
     ensureRareData().m_inlineBoxWrapper = boxWrapper;
 }
 
 } // namespace blink
 
 #endif // RenderBox_h