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

Source/core/rendering/RenderPagedFlowThread.h

Index: Source/core/rendering/RenderPagedFlowThread.h
diff --git a/Source/core/rendering/RenderPagedFlowThread.h b/Source/core/rendering/RenderPagedFlowThread.h
index 10e6f5f9310409a16548c2337cd825ac990f8abd..0206ea2bdce4711eb8afd6331c6ecdda2de7343a 100644
--- a/Source/core/rendering/RenderPagedFlowThread.h
+++ b/Source/core/rendering/RenderPagedFlowThread.h
@@ -20,7 +20,6 @@ public:
     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;