Move computeInlineBoxPosition() out from VisiblePosition

Source/core/editing/VisiblePosition.h

Index: Source/core/editing/VisiblePosition.h
diff --git a/Source/core/editing/VisiblePosition.h b/Source/core/editing/VisiblePosition.h
index 9daa7a08861bf3916d987321c71ba0c16945dce2..20172c7b503bd793ade28288e3409e0475e0d751 100644
--- a/Source/core/editing/VisiblePosition.h
+++ b/Source/core/editing/VisiblePosition.h
@@ -110,11 +110,6 @@ public:
     // FIXME: This does not handle [table, 0] correctly.
     Element* rootEditableElement() const { return m_deepPosition.isNotNull() ? m_deepPosition.anchorNode()->rootEditableElement() : 0; }
 
-    InlineBoxPosition computeInlineBoxPosition() const
-    {
-        return m_deepPosition.computeInlineBoxPosition(m_affinity);
-    }
-
     // Rect is local to the returned layoutObject
     LayoutRect localCaretRect(LayoutObject*&) const;
     // Bounds of (possibly transformed) caret in absolute coords
@@ -142,6 +137,13 @@ private:
     EAffinity m_affinity;
 };
 
+// TODO(yosin) We should move |computeInlineBoxPosition()| to "VisibleUnits.h"
+// with |Position| version.
+inline InlineBoxPosition computeInlineBoxPosition(const VisiblePosition& position)
+{
+    return position.deepEquivalent().computeInlineBoxPosition(position.affinity());
+}
+
 EphemeralRange makeRange(const VisiblePosition&, const VisiblePosition&);
 
 CORE_EXPORT Position canonicalPositionOf(const Position&);