Make VisiblePosition constructor private

Source/modules/accessibility/AXLayoutObject.cpp

Index: Source/modules/accessibility/AXLayoutObject.cpp
diff --git a/Source/modules/accessibility/AXLayoutObject.cpp b/Source/modules/accessibility/AXLayoutObject.cpp
index 00fc26dfce5896778f4f1a3ba173498a0c73c941..cc000ca43d94c1f2a69d7b8d2ed8ec020c199828 100644
--- a/Source/modules/accessibility/AXLayoutObject.cpp
+++ b/Source/modules/accessibility/AXLayoutObject.cpp
@@ -2185,7 +2185,7 @@ VisiblePosition AXLayoutObject::visiblePositionForIndex(int index) const
         return VisiblePosition();
 
     if (index <= 0)
-        return VisiblePosition(firstPositionInOrBeforeNode(node));
+        return createVisiblePosition(firstPositionInOrBeforeNode(node));
 
     Position start, end;
     bool selected = Range::selectNodeContents(node, start, end);
@@ -2194,7 +2194,7 @@ VisiblePosition AXLayoutObject::visiblePositionForIndex(int index) const
 
     CharacterIterator it(start, end);
     it.advance(index - 1);
-    return VisiblePosition(Position(it.currentContainer(), it.endOffset()), TextAffinity::Upstream);
+    return createVisiblePosition(Position(it.currentContainer(), it.endOffset()), TextAffinity::Upstream);
 }
 
 void AXLayoutObject::addInlineTextBoxChildren(bool force)