[New Multicolumn] Make fast/multicol/overflow-content.html pass in the new implementation.

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 1512 matching lines @@
 
         if (needsPositionedMovementLayout() && !tryLayoutDoingPositionedMovementOnly())
             return false;
 
         FastTextAutosizer::LayoutScope fastTextAutosizerLayoutScope(this);
 
         // Lay out positioned descendants or objects that just need to recompute overflow.
         if (needsSimplifiedNormalFlowLayout())
             simplifiedNormalFlowLayout();
 
-        // Make sure a forced break is applied after the content if we are a flow thread in a simplified layout.
-        // This ensures the size information is correctly computed for the last auto-height region receiving content.
-        if (isRenderFlowThread())
-            toRenderFlowThread(this)->applyBreakAfterContent(clientLogicalBottom());

[Julien - ping for review, 2014/05/07 01:01:11]

Shouldn't we call recalculateColumnHeight as our height could have changed (due
to children changing size)?

-
         // Lay out our positioned objects if our positioned child bit is set.
         // Also, if an absolute position element inside a relative positioned container moves, and the absolute element has a fixed position
         // child, neither the fixed element nor its container learn of the movement since posChildNeedsLayout() is only marked as far as the
         // relative positioned container. So if we can have fixed pos objects in our positioned objects list check if any of them
         // are statically positioned and thus need to move with their absolute ancestors.
         bool canContainFixedPosObjects = canContainFixedPositionObjects();
         if (posChildNeedsLayout() || needsPositionedMovementLayout() || canContainFixedPosObjects)
             layoutPositionedObjects(false, needsPositionedMovementLayout() ? ForcedLayoutAfterContainingBlockMoved : (!posChildNeedsLayout() && canContainFixedPosObjects ? LayoutOnlyFixedPositionedObjects : DefaultLayout));
 
         // Recompute our overflow information.
@@ skipping 3425 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