[New Multicolumn] Actual support for layout of column-span:all.

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 283 matching lines @@
     //////////////////////////////////////////
 private:
 #if ENABLE(ASSERT)
     bool isSetNeedsLayoutForbidden() const { return m_setNeedsLayoutForbidden; }
     void setNeedsLayoutIsForbidden(bool flag) { m_setNeedsLayoutForbidden = flag; }
 #endif
 
     void addAbsoluteRectForLayer(LayoutRect& result);
     bool requiresAnonymousTableWrappers(const RenderObject*) const;
 
+    // This renderer has column-span:all, but is it really a valid column spanner?
+    bool isValidColumnSpanAll() const;
+
     // Gets pseudoStyle from Shadow host(in case of input elements)
     // or from Parent element.
     PassRefPtr<RenderStyle> getUncachedPseudoStyleFromParentOrShadowHost() const;
 
     bool skipInvalidationWhenLaidOutChildren() const;
 
 public:
 #ifndef NDEBUG
     void showTreeForThis() const;
     void showRenderTreeForThis() const;
@@ skipping 314 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 and :after
     // 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(); }
 
+    bool isColumnSpanAll() const { return style()->columnSpan() == ColumnSpanAll && isValidColumnSpanAll(); }
+
     // 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 966 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