Move DragCaretController class to its own file

Source/core/editing/Caret.h

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple 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 56 matching lines @@
 
     static LayoutBlock* caretLayoutObject(Node*);
     static void invalidateLocalCaretRect(Node*, const LayoutRect&);
 
 private:
     LayoutBlock* m_caretPainter; // layout object responsible for painting the caret
     LayoutRect m_caretLocalRect; // caret rect in coords local to the layoutObject responsible for painting the caret
     CaretVisibility m_caretVisibility;
 };
 
-class DragCaretController final : public NoBaseWillBeGarbageCollected<DragCaretController>, private CaretBase {
-    WTF_MAKE_NONCOPYABLE(DragCaretController);
-    WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED(DragCaretController);
-public:
-    static PassOwnPtrWillBeRawPtr<DragCaretController> create();
-
-    LayoutBlock* caretLayoutObject() const { return CaretBase::caretPainter(); }
-    void paintDragCaret(LocalFrame*, GraphicsContext*, const LayoutPoint&, const LayoutRect& clipRect) const;
-
-    bool isContentEditable() const { return m_position.rootEditableElement(); }
-    bool isContentRichlyEditable() const;
-
-    bool hasCaret() const { return m_position.isNotNull(); }
-    const VisiblePosition& caretPosition() { return m_position; }
-    void setCaretPosition(const VisiblePosition&);
-    void clear() { setCaretPosition(VisiblePosition()); }
-
-    void nodeWillBeRemoved(Node&);
-
-    DECLARE_TRACE();
-
-private:
-    DragCaretController();
-
-    VisiblePosition m_position;
-};
-
 } // namespace blink
 
-
 #endif // Caret_h