Introduce enum class TextAffinity as replacement of enum EAffinity

Source/core/editing/commands/CreateLinkCommand.cpp

 /*
  * Copyright (C) 2006 Apple Computer, 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 33 matching lines @@
 
     RefPtrWillBeRawPtr<HTMLAnchorElement> anchorElement = HTMLAnchorElement::create(document());
     anchorElement->setHref(AtomicString(m_url));
 
     if (endingSelection().isRange()) {
         applyStyledElement(anchorElement.get());
     } else {
         insertNodeAt(anchorElement.get(), endingSelection().start());
         RefPtrWillBeRawPtr<Text> textNode = Text::create(document(), m_url);
         appendNode(textNode.get(), anchorElement.get());
-        setEndingSelection(VisibleSelection(positionInParentBeforeNode(*anchorElement), positionInParentAfterNode(*anchorElement), DOWNSTREAM, endingSelection().isDirectional()));
+        setEndingSelection(VisibleSelection(positionInParentBeforeNode(*anchorElement), positionInParentAfterNode(*anchorElement), TextAffinity::Downstream, endingSelection().isDirectional()));
     }
 }
 
 }