Adjust constness to avoid const_cast.

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

 /*
  * 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, 2011 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. 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
@@ skipping 1981 matching lines @@
     }
     if (!haveNormalFlowChild && hasLineIfEmpty()) {
         const FontMetrics& fontMetrics = firstLineStyle()->getFontMetrics();
         return fontMetrics.ascent()
             + (lineHeight(true, lineDirection, PositionOfInteriorLineBoxes) - fontMetrics.height()) / 2
             + (lineDirection == HorizontalLine ? borderTop() + paddingTop() : borderRight() + paddingRight());
     }
     return -1;
 }
 
-LayoutBlock* LayoutBlock::enclosingFirstLineStyleBlock() const
+const LayoutBlock* LayoutBlock::enclosingFirstLineStyleBlock() const
 {
-    LayoutBlock* firstLineBlock = const_cast<LayoutBlock*>(this);
+    const LayoutBlock* firstLineBlock = this;
     bool hasPseudo = false;
     while (true) {
         hasPseudo = firstLineBlock->style()->hasPseudoStyle(PseudoIdFirstLine);
         if (hasPseudo)
             break;
         LayoutObject* parentBlock = firstLineBlock->parent();
         if (firstLineBlock->isAtomicInlineLevel() || firstLineBlock->isFloatingOrOutOfFlowPositioned()
             || !parentBlock
             || !parentBlock->canHaveFirstLineOrFirstLetterStyle())
             break;
         ASSERT_WITH_SECURITY_IMPLICATION(parentBlock->isLayoutBlock());
         if (toLayoutBlock(parentBlock)->firstChild() != firstLineBlock)
             break;
         firstLineBlock = toLayoutBlock(parentBlock);
     }
 
     if (!hasPseudo)
         return nullptr;
 
     return firstLineBlock;
 }
 
-LayoutBlockFlow* LayoutBlock::nearestInnerBlockWithFirstLine() const
+LayoutBlockFlow* LayoutBlock::nearestInnerBlockWithFirstLine()

[eae, 2016/05/10 15:40:54]

Can this return a const LayoutBlockFlow?

[mstensho (USE GERRIT), 2016/05/10 15:58:16]

The caller calls non-const methods on the returned object, so it doesn't seem
like a good idea.

 {
     if (childrenInline())
-        return toLayoutBlockFlow(const_cast<LayoutBlock*>(this));
+        return toLayoutBlockFlow(this);

[eae, 2016/05/10 15:40:54]

Could we add a const version of toLayoutBlockFlow instead? 

[mstensho (USE GERRIT), 2016/05/10 15:58:16]

The DEFINE_LAYOUT_OBJECT_TYPE_CASTS macro already takes care of that.

     for (LayoutObject* child = firstChild(); child && !child->isFloatingOrOutOfFlowPositioned() && child->isLayoutBlockFlow(); child = toLayoutBlock(child)->firstChild()) {
         if (child->childrenInline())
             return toLayoutBlockFlow(child);
     }
     return nullptr;
 }
 
 void LayoutBlock::absoluteRects(Vector<IntRect>& rects, const LayoutPoint& accumulatedOffset) const
 {
     // For blocks inside inlines, we go ahead and include margins so that we run right up to the
@@ skipping 338 matching lines @@
         for (TrackedLayoutBoxListHashSet::const_iterator it = positionedDescendantSet->begin(); it != end; ++it) {
             LayoutBox* currBox = *it;
             ASSERT(!currBox->needsLayout());
         }
     }
 }
 
 #endif
 
 } // namespace blink