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

Source/core/rendering/RenderObject.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google 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
@@ skipping 49 matching lines @@
 class InlineBox;
 class Position;
 class PositionWithAffinity;
 class PseudoStyleRequest;
 class RenderBoxModelObject;
 class RenderBlock;
 class RenderFlowThread;
 class RenderGeometryMap;
 class RenderLayer;
 class RenderLayerModelObject;
+class RenderMultiColumnSpannerPlaceholder;
 class RenderView;
 class TransformState;
 
 struct PaintInfo;
 
 enum CursorDirective {
     SetCursorBasedOnStyle,
     SetCursor,
     DoNotSetCursor
 };
@@ skipping 270 matching lines @@
     bool isMeter() const { return isOfType(RenderObjectMeter); }
     bool isProgress() const { return isOfType(RenderObjectProgress); }
     bool isQuote() const { return isOfType(RenderObjectQuote); }
     bool isRenderButton() const { return isOfType(RenderObjectRenderButton); }
     bool isRenderFullScreen() const { return isOfType(RenderObjectRenderFullScreen); }
     bool isRenderFullScreenPlaceholder() const { return isOfType(RenderObjectRenderFullScreenPlaceholder); }
     bool isRenderGrid() const { return isOfType(RenderObjectRenderGrid); }
     bool isRenderIFrame() const { return isOfType(RenderObjectRenderIFrame); }
     bool isRenderImage() const { return isOfType(RenderObjectRenderImage); }
     bool isRenderMultiColumnSet() const { return isOfType(RenderObjectRenderMultiColumnSet); }
-    bool isRenderMultiColumnSpannerSet() const { return isOfType(RenderObjectRenderMultiColumnSpannerSet); }
+    bool isRenderMultiColumnSpannerPlaceholder() const { return isOfType(RenderObjectRenderMultiColumnSpannerPlaceholder); }
     bool isRenderRegion() const { return isOfType(RenderObjectRenderRegion); }
     bool isRenderScrollbarPart() const { return isOfType(RenderObjectRenderScrollbarPart); }
     bool isRenderTableCol() const { return isOfType(RenderObjectRenderTableCol); }
     bool isRenderView() const { return isOfType(RenderObjectRenderView); }
     bool isReplica() const { return isOfType(RenderObjectReplica); }
     bool isRuby() const { return isOfType(RenderObjectRuby); }
     bool isRubyBase() const { return isOfType(RenderObjectRubyBase); }
     bool isRubyRun() const { return isOfType(RenderObjectRubyRun); }
     bool isRubyText() const { return isOfType(RenderObjectRubyText); }
     bool isSlider() const { return isOfType(RenderObjectSlider); }
@@ skipping 254 matching lines @@
     void clearNode() { m_node = nullptr; }
 
     // Returns the styled node that caused the generation of this renderer.
     // This is the same as node() except for renderers of :before, :after and
     // :first-letter pseudo elements for which their parent node is returned.
     Node* generatingNode() const { return isPseudoElement() ? node()->parentOrShadowHostNode() : node(); }
 
     Document& document() const { return m_node->document(); }
     LocalFrame* frame() const { return document().frame(); }
 
+    virtual RenderMultiColumnSpannerPlaceholder* spannerPlaceholder() const { return 0; }
+    bool isColumnSpanAll() const { return style()->columnSpan() == ColumnSpanAll && spannerPlaceholder(); }
+
     // Returns the object containing this one. Can be different from parent for positioned elements.
     // If paintInvalidationContainer and paintInvalidationContainerSkipped are not null, on return *paintInvalidationContainerSkipped
     // is true if the renderer returned is an ancestor of paintInvalidationContainer.
     RenderObject* container(const RenderLayerModelObject* paintInvalidationContainer = 0, bool* paintInvalidationContainerSkipped = 0) const;
     RenderBlock* containerForFixedPosition(const RenderLayerModelObject* paintInvalidationContainer = 0, bool* paintInvalidationContainerSkipped = 0) const;
 
     virtual RenderObject* hoverAncestor() const { return parent(); }
 
     Element* offsetParent() const;
 
@@ skipping 432 matching lines @@
         RenderObjectQuote,
         RenderObjectRenderButton,
         RenderObjectRenderFlowThread,
         RenderObjectRenderFullScreen,
         RenderObjectRenderFullScreenPlaceholder,
         RenderObjectRenderGrid,
         RenderObjectRenderIFrame,
         RenderObjectRenderImage,
         RenderObjectRenderInline,
         RenderObjectRenderMultiColumnSet,
-        RenderObjectRenderMultiColumnSpannerSet,
+        RenderObjectRenderMultiColumnSpannerPlaceholder,
         RenderObjectRenderPart,
         RenderObjectRenderRegion,
         RenderObjectRenderScrollbarPart,
         RenderObjectRenderTableCol,
         RenderObjectRenderView,
         RenderObjectReplica,
         RenderObjectRuby,
         RenderObjectRubyBase,
         RenderObjectRubyRun,
         RenderObjectRubyText,
@@ skipping 519 matching lines @@
 void showTree(const blink::RenderObject*);
 void showLineTree(const blink::RenderObject*);
 void showRenderTree(const blink::RenderObject* object1);
 // We don't make object2 an optional parameter so that showRenderTree
 // can be called from gdb easily.
 void showRenderTree(const blink::RenderObject* object1, const blink::RenderObject* object2);
 
 #endif
 
 #endif // RenderObject_h