Introduce enum class TextAffinity as replacement of enum EAffinity

Source/core/html/HTMLTextFormControlElementTest.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/html/HTMLTextFormControlElement.h"
 
 #include "core/dom/Text.h"
 #include "core/editing/FrameSelection.h"
 #include "core/editing/Position.h"
@@ skipping 194 matching lines @@
 }
 
 TEST_F(HTMLTextFormControlElementTest, SpellCheckDoesNotCauseUpdateLayout)
 {
     HTMLInputElement* input = toHTMLInputElement(document().getElementById("input"));
     input->focus();
     input->setValue("Hello, input field");
     VisibleSelection oldSelection = document().frame()->selection().selection();
 
     Position newPosition(input->innerEditorElement()->firstChild(), 3);
-    VisibleSelection newSelection(newPosition, DOWNSTREAM);
+    VisibleSelection newSelection(newPosition, TextAffinity::Downstream);
     document().frame()->selection().setSelection(newSelection, FrameSelection::CloseTyping | FrameSelection::ClearTypingStyle | FrameSelection::DoNotUpdateAppearance);
     ASSERT_EQ(3, input->selectionStart());
 
     OwnPtrWillBePersistent<SpellChecker> spellChecker(SpellChecker::create(page().frame()));
     forceLayoutFlag();
     int startCount = layoutCount();
     spellChecker->respondToChangedSelection(oldSelection, FrameSelection::CloseTyping | FrameSelection::ClearTypingStyle);
     EXPECT_EQ(startCount, layoutCount());
 }
 
 } // namespace blink