[New Multicolumn] Add support for column-span:all

Source/core/rendering/RenderPagedFlowThread.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef RenderPagedFlowThread_h
 #define RenderPagedFlowThread_h
 
 #include "core/rendering/RenderMultiColumnFlowThread.h"
 
 namespace blink {
 
 // A flow thread for paged overflow. FIXME: The current implementation relies on the multicol
 // implementation, but it in the long run it would be better to have what's common between
 // RenderMultiColumnFlowThread and RenderPagedFlowThread in RenderFlowThread, and have both of them
 // inherit from that one.
 class RenderPagedFlowThread : public RenderMultiColumnFlowThread {
 public:
     static RenderPagedFlowThread* createAnonymous(Document&, RenderStyle* parentStyle);
 
     RenderBlockFlow* pagedBlockFlow() const { return toRenderBlockFlow(parent()); }
 
     virtual bool isRenderPagedFlowThread() const OVERRIDE { return true; }
-    virtual bool heightIsAuto() const OVERRIDE { return !columnHeightAvailable(); }
     virtual const char* renderName() const OVERRIDE;
     virtual bool needsNewWidth() const OVERRIDE;
     virtual void updateLogicalWidth() OVERRIDE;
     virtual void layout();
+
+private:
+    virtual bool isDescendantValidColumnSpanner(RenderObject* /*descendant*/) const OVERRIDE { return false; }
 };
 
 } // namespace blink
 
 #endif // RenderPagedFlowThread_h