Introduce visiblePositionOf() with PositionWithAffinity as replacement of VisiblePosition constructo

Source/core/editing/DragCaretController.cpp

 /*
  * Copyright (C) 2004, 2008, 2009, 2010 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 38 matching lines @@
 
 void DragCaretController::setCaretPosition(const PositionWithAffinity& position)
 {
     // for querying Layer::compositingState()
     // This code is probably correct, since it doesn't occur in a stack that
     // involves updating compositing state.
     DisableCompositingQueryAsserts disabler;
 
     if (Node* node = m_position.deepEquivalent().anchorNode())
         invalidateCaretRect(node);
-    m_position = VisiblePosition(position);
+    m_position = visiblePositionOf(position);
     Document* document = nullptr;
     if (Node* node = m_position.deepEquivalent().anchorNode()) {
         invalidateCaretRect(node);
         document = &node->document();
     }
     if (m_position.isNull() || m_position.isOrphan()) {
         clearCaretRect();
     } else {
         document->updateLayoutTreeIfNeeded();
         updateCaretRect(m_position);
@@ skipping 42 matching lines @@
     return rootEditableElementOf(m_position);
 }
 
 void DragCaretController::paintDragCaret(LocalFrame* frame, GraphicsContext* p, const LayoutPoint& paintOffset, const LayoutRect& clipRect) const
 {
     if (m_position.deepEquivalent().anchorNode()->document().frame() == frame)
         paintCaret(m_position.deepEquivalent().anchorNode(), p, paintOffset, clipRect);
 }
 
 } // namespace blink