Add support for the column-fill property.

Source/core/rendering/RenderBlock.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. 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
@@ skipping 6456 matching lines @@
         LayoutUnit pageLogicalHeightAtNewOffset = hasUniformPageLogicalHeight ? pageLogicalHeight : pageLogicalHeightForOffset(logicalOffset + remainingLogicalHeight);
         setPageBreak(logicalOffset, lineHeight - remainingLogicalHeight);
         if (((lineBox == firstRootBox() && totalLogicalHeight < pageLogicalHeightAtNewOffset) || (!style()->hasAutoOrphans() && style()->orphans() >= lineCount(lineBox)))
             && !isOutOfFlowPositioned() && !isTableCell())
             setPaginationStrut(remainingLogicalHeight + max<LayoutUnit>(0, logicalOffset));
         else {
             delta += remainingLogicalHeight;
             lineBox->setPaginationStrut(remainingLogicalHeight);
             lineBox->setIsFirstAfterPageBreak(true);
         }
-    } else if (remainingLogicalHeight == pageLogicalHeight && lineBox != firstRootBox())
-        lineBox->setIsFirstAfterPageBreak(true);
+    } else if (remainingLogicalHeight == pageLogicalHeight) {
+        // We're at the very top of a page or column.
+        if (lineBox != firstRootBox())
+            lineBox->setIsFirstAfterPageBreak(true);
+        if (lineBox != firstRootBox() || offsetFromLogicalTopOfFirstPage())
+            setPageBreak(logicalOffset, lineHeight);
+    }
 }
 
 bool RenderBlock::lineWidthForPaginatedLineChanged(RootInlineBox* rootBox, LayoutUnit lineDelta, RenderFlowThread* flowThread) const
 {
     if (!flowThread)
         return false;
 
     RenderRegion* currentRegion = regionAtBlockOffset(rootBox->lineTopWithLeading() + lineDelta);
     // Just bail if the region didn't change.
     if (rootBox->containingRegion() == currentRegion)
@@ skipping 312 matching lines @@
 void RenderBlock::showLineTreeAndMark(const InlineBox* markedBox1, const char* markedLabel1, const InlineBox* markedBox2, const char* markedLabel2, const RenderObject* obj) const
 {
     showRenderObject();
     for (const RootInlineBox* root = firstRootBox(); root; root = root->nextRootBox())
         root->showLineTreeAndMark(markedBox1, markedLabel1, markedBox2, markedLabel2, obj, 1);
 }
 
 #endif
 
 } // namespace WebCore