Introduce enum class TextAffinity as replacement of enum EAffinity

Source/core/editing/commands/ApplyBlockElementCommand.cpp

 /*
  * Copyright (C) 2006, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google 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
@@ skipping 98 matching lines @@
 void ApplyBlockElementCommand::formatSelection(const VisiblePosition& startOfSelection, const VisiblePosition& endOfSelection)
 {
     // Special case empty unsplittable elements because there's nothing to split
     // and there's nothing to move.
     Position start = startOfSelection.deepEquivalent().downstream();
     if (isAtUnsplittableElement(start)) {
         RefPtrWillBeRawPtr<HTMLElement> blockquote = createBlockElement();
         insertNodeAt(blockquote, start);
         RefPtrWillBeRawPtr<HTMLBRElement> placeholder = createBreakElement(document());
         appendNode(placeholder, blockquote);
-        setEndingSelection(VisibleSelection(positionBeforeNode(placeholder.get()), DOWNSTREAM, endingSelection().isDirectional()));
+        setEndingSelection(VisibleSelection(positionBeforeNode(placeholder.get()), TextAffinity::Downstream, endingSelection().isDirectional()));
         return;
     }
 
     RefPtrWillBeRawPtr<HTMLElement> blockquoteForNextIndent = nullptr;
     VisiblePosition endOfCurrentParagraph = endOfParagraph(startOfSelection);
     VisiblePosition endOfLastParagraph = endOfParagraph(endOfSelection);
     VisiblePosition endAfterSelection = endOfParagraph(endOfLastParagraph.next());
     m_endOfLastParagraph = endOfLastParagraph.deepEquivalent();
 
     bool atEnd = false;
@@ skipping 160 matching lines @@
     return element.release();
 }
 
 DEFINE_TRACE(ApplyBlockElementCommand)
 {
     visitor->trace(m_endOfLastParagraph);
     CompositeEditCommand::trace(visitor);
 }
 
 }