Adjust constness to avoid const_cast.

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 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 258 matching lines @@
     // </style>
     // <div id="enclosingFirstLineStyleBlock">
     //   <div>
     //     <div id="nearestInnerBlockWithFirstLine">
     //       [<span>]first line text[</span>]
     //     </div>
     //   </div>
     // </div>
 
     // Returns the nearest enclosing block (including this block) that contributes a first-line style to our first line.
-    LayoutBlock* enclosingFirstLineStyleBlock() const;
+    const LayoutBlock* enclosingFirstLineStyleBlock() const;
     // Returns this block or the nearest inner block containing the actual first line.
-    LayoutBlockFlow* nearestInnerBlockWithFirstLine() const;
+    LayoutBlockFlow* nearestInnerBlockWithFirstLine();
 
 protected:
     void willBeDestroyed() override;
 
     void dirtyForLayoutFromPercentageHeightDescendants(SubtreeLayoutScope&);
 
     void layout() override;
 
     enum PositionedLayoutBehavior {
         DefaultLayout,
@@ skipping 200 matching lines @@
     // FIXME: This is temporary as we move code that accesses block flow
     // member variables out of LayoutBlock and into LayoutBlockFlow.
     friend class LayoutBlockFlow;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutBlock, isLayoutBlock());
 
 } // namespace blink
 
 #endif // LayoutBlock_h