Cleanup: Replace adjustForColumns() / offsetForColumns() with columnOffset().

Source/core/rendering/RenderObject.h

Index: Source/core/rendering/RenderObject.h
diff --git a/Source/core/rendering/RenderObject.h b/Source/core/rendering/RenderObject.h
index c4bfcb1cee3d12b28f1decb8f11b87dcb084c737..11fd0c58ec2ec66550abaf83edb79b47c19efaa2 100644
--- a/Source/core/rendering/RenderObject.h
+++ b/Source/core/rendering/RenderObject.h
@@ -851,15 +851,9 @@ public:
     virtual void computeRectForRepaint(const RenderLayerModelObject* repaintContainer, LayoutRect&, bool fixed = false) const;
     virtual void computeFloatRectForRepaint(const RenderLayerModelObject* repaintContainer, FloatRect& repaintRect, bool fixed = false) const;
 
-    // If multiple-column layout results in applying an offset to the given point, add the same
-    // offset to the given size.
-    virtual void adjustForColumns(LayoutSize&, const LayoutPoint&) const { }
-    LayoutSize offsetForColumns(const LayoutPoint& point) const
-    {
-        LayoutSize offset;
-        adjustForColumns(offset, point);
-        return offset;
-    }
+    // Return the offset to the column in which the specified point (in flow-thread coordinates)
+    // lives. This is used to convert a flow-thread point to a visual point.
+    virtual LayoutSize columnOffset(const LayoutPoint&) const { return LayoutSize(); }
 
     virtual unsigned length() const { return 1; }