blink: Cleanup class/struct forward declarations

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2006, 2007, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google 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 39 matching lines @@
 enum : uint32_t {
   BackgroundPaintInGraphicsLayer = 1 << 0,
   BackgroundPaintInScrollingContents = 1 << 1
 };
 using BackgroundPaintLocation = uint32_t;
 
 // Modes for some of the line-related functions.
 enum LinePositionMode { PositionOnContainingLine, PositionOfInteriorLineBoxes };
 enum LineDirectionMode { HorizontalLine, VerticalLine };
 
-class InlineFlowBox;
-
 struct LayoutBoxModelObjectRareData {
   WTF_MAKE_NONCOPYABLE(LayoutBoxModelObjectRareData);
   USING_FAST_MALLOC(LayoutBoxModelObjectRareData);
 
  public:
   LayoutBoxModelObjectRareData() {}
 
   StickyPositionScrollingConstraints m_stickyPositionScrollingConstraints;
 };
 
@@ skipping 454 matching lines @@
   std::unique_ptr<PaintLayer> m_layer;
 
   std::unique_ptr<LayoutBoxModelObjectRareData> m_rareData;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutBoxModelObject, isBoxModelObject());
 
 }  // namespace blink
 
 #endif  // LayoutBoxModelObject_h