Introduce enum class TextAffinity as replacement of enum EAffinity

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 a06825021a2527ad2fb08b4829b5339980e50dc7..8b6e2ac089230a9f4affb93aeb45527055f53aae 100644
--- a/Source/modules/accessibility/AXLayoutObject.cpp
+++ b/Source/modules/accessibility/AXLayoutObject.cpp
@@ -38,6 +38,7 @@
 #include "core/editing/EditingUtilities.h"
 #include "core/editing/FrameSelection.h"
 #include "core/editing/RenderedPosition.h"
+#include "core/editing/TextAffinity.h"
 #include "core/editing/VisibleUnits.h"
 #include "core/editing/iterators/CharacterIterator.h"
 #include "core/editing/iterators/TextIterator.h"
@@ -2185,7 +2186,7 @@ VisiblePosition AXLayoutObject::visiblePositionForIndex(int index) const
 
     CharacterIterator it(start, end);
     it.advance(index - 1);
-    return VisiblePosition(Position(it.currentContainer(), it.endOffset()), UPSTREAM);
+    return VisiblePosition(Position(it.currentContainer(), it.endOffset()), TextAffinity::Upstream);
 }
 
 void AXLayoutObject::addInlineTextBoxChildren(bool force)