[New Multicolumn] Add support for 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 341 matching lines @@
     virtual bool isRenderBlockFlow() const { return false; }
     virtual bool isRenderButton() const { return false; }
     virtual bool isRenderFlowThread() const { return false; }
     virtual bool isRenderFullScreen() const { return false; }
     virtual bool isRenderFullScreenPlaceholder() const { return false; }
     virtual bool isRenderGrid() const { return false; }
     virtual bool isRenderIFrame() const { return false; }
     virtual bool isRenderImage() const { return false; }
     virtual bool isRenderInline() const { return false; }
     virtual bool isRenderMultiColumnSet() const { return false; }
+    virtual bool isRenderMultiColumnSpannerPlaceholder() const { return false; }
     virtual bool isRenderPart() const { return false; }
     virtual bool isRenderRegion() const { return false; }
     virtual bool isRenderScrollbarPart() const { return false; }
     virtual bool isRenderTableCol() const { return false; }
     virtual bool isRenderView() const { return false; }
     virtual bool isReplica() const { return false; }
     virtual bool isRuby() const { return false; }
     virtual bool isRubyBase() const { return false; }
     virtual bool isRubyRun() const { return false; }
     virtual bool isRubyText() const { return false; }
@@ skipping 111 matching lines @@
         return true;
     }
 
     bool isAnonymous() const { return m_bitfields.isAnonymous(); }
     bool isAnonymousBlock() const
     {
         // This function is kept in sync with anonymous block creation conditions in
         // RenderBlock::createAnonymousBlock(). This includes creating an anonymous
         // RenderBlock having a BLOCK or BOX display. Other classes such as RenderTextFragment
         // are not RenderBlocks and will return false. See https://bugs.webkit.org/show_bug.cgi?id=56709.
-        return isAnonymous() && (style()->display() == BLOCK || style()->display() == BOX) && style()->styleType() == NOPSEUDO && isRenderBlock() && !isListMarker() && !isRenderFlowThread()
+        return isAnonymous() && (style()->display() == BLOCK || style()->display() == BOX) && style()->styleType() == NOPSEUDO && isRenderBlock() && !isListMarker() && !isRenderFlowThread() && !isRenderMultiColumnSet()

[rune, 2014/07/01 08:41:39]

I guess the added check here is because of
RenderMultiColumnSpannerPlaceholder::createAnonymous(). Then why isn't this
testing isRenderMultiColumnSpannerPlaceholder() ?

[mstensho (USE GERRIT), 2014/08/26 09:43:58]

It's here to make sure that a column set isn't treated as a "regular" anonymous
block (as defined in CSS 2.1). Regular anonymous blocks may be deleted, merged
and split when contents require it (take a look at what happens deep inside
RenderBlock's addChild() and removeChild()). We don't want any of that to happen
to column sets. A spanner placeholder isn't a RenderBlock, so it's not necessary
to test for it here.

[rune, 2014/08/27 07:00:01]

Acknowledged.

             && !isRenderFullScreen()
             && !isRenderFullScreenPlaceholder();
     }
     bool isAnonymousColumnsBlock() const { return style()->specifiesColumns() && isAnonymousBlock(); }
     bool isAnonymousColumnSpanBlock() const { return style()->columnSpan() && isAnonymousBlock(); }
     bool isElementContinuation() const { return node() && node()->renderer() != this; }
     bool isInlineElementContinuation() const { return isElementContinuation() && isInline(); }
     virtual RenderBoxModelObject* virtualContinuation() const { return 0; }
 
     bool isFloating() const { return m_bitfields.floating(); }
@@ skipping 974 matching lines @@
 void showTree(const WebCore::RenderObject*);
 void showLineTree(const WebCore::RenderObject*);
 void showRenderTree(const WebCore::RenderObject* object1);
 // We don't make object2 an optional parameter so that showRenderTree
 // can be called from gdb easily.
 void showRenderTree(const WebCore::RenderObject* object1, const WebCore::RenderObject* object2);
 
 #endif
 
 #endif // RenderObject_h