Making LayoutUnit conversions to Float type explicit

Source/core/rendering/RenderMultiColumnSet.h

Index: Source/core/rendering/RenderMultiColumnSet.h
diff --git a/Source/core/rendering/RenderMultiColumnSet.h b/Source/core/rendering/RenderMultiColumnSet.h
index da7a78385dd01658ab0746552e2de9b6a423a558..d858b23b3d3e61af8d10de58bcd20fa0687dd414 100644
--- a/Source/core/rendering/RenderMultiColumnSet.h
+++ b/Source/core/rendering/RenderMultiColumnSet.h
@@ -161,7 +161,7 @@ private:
 
         // Return the column height that this content run would require, considering the implicit
         // breaks assumed so far.
-        LayoutUnit columnLogicalHeight(LayoutUnit startOffset) const { return ceilf(float(m_breakOffset - startOffset) / float(m_assumedImplicitBreaks + 1)); }
+        LayoutUnit columnLogicalHeight(LayoutUnit startOffset) const { return ceilf((m_breakOffset - startOffset).toFloat() / float(m_assumedImplicitBreaks + 1)); }
 
     private:
         LayoutUnit m_breakOffset; // Flow thread offset where this run ends.