Move LayoutObject::previousOffsetForBackwardDeletion() to editing.

third_party/WebKit/Source/core/layout/LayoutText.h

 /*
  * (C) 1999 Lars Knoll (knoll@kde.org)
  * (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004-2009, 2013 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 143 matching lines @@
     InlineTextBox* firstTextBox() const { return m_firstTextBox; }
     InlineTextBox* lastTextBox() const { return m_lastTextBox; }
 
     // True if we have inline text box children which implies rendered text (or whitespace) output.
     bool hasTextBoxes() const { return firstTextBox(); }
 
     int caretMinOffset() const override;
     int caretMaxOffset() const override;
     unsigned resolvedTextLength() const;
 
-    int previousOffsetForBackwardDeletion(int current) const final;
-
     bool containsReversedText() const { return m_containsReversedText; }
 
     bool isSecure() const { return style()->textSecurity() != TSNONE; }
     void momentarilyRevealLastTypedCharacter(unsigned lastTypedCharacterOffset);
 
     bool isAllCollapsibleWhitespace() const;
     bool isRenderedCharacter(int offsetInNode) const;
 
     // TODO(eae): Rename and change to only handle the word measurements use
     // case once the simple code path has been removed. crbug.com/404597
@@ skipping 117 matching lines @@
 inline LayoutText* Text::layoutObject() const
 {
     return toLayoutText(CharacterData::layoutObject());
 }
 
 void applyTextTransform(const ComputedStyle*, String&, UChar);
 
 } // namespace blink
 
 #endif // LayoutText_h