blink: Cleanup core class forward declarations

third_party/WebKit/Source/core/paint/GridPainter.h

 // 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.
 
 #ifndef GridPainter_h
 #define GridPainter_h
 
 #include "wtf/Allocator.h"
 
 namespace blink {
 
 struct PaintInfo;
 class LayoutPoint;
-class LayoutBox;
 class LayoutGrid;
 
 class GridPainter {
   STACK_ALLOCATED();
 
  public:
   GridPainter(const LayoutGrid& layoutGrid) : m_layoutGrid(layoutGrid) {}
 
   void paintChildren(const PaintInfo&, const LayoutPoint&);
 
  private:
   const LayoutGrid& m_layoutGrid;
 };
 
 }  // namespace blink
 
 #endif  // GridPainter_h