Use the baseline information exposed by C++ to pipe baseline data through RenderBox.

sky/engine/core/rendering/RenderBox.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2006, 2007 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 411 matching lines @@
         updateLogicalHeight();
         return true;
     }
 
     virtual PositionWithAffinity positionForPoint(const LayoutPoint&) override;
 
     void removeFloatingOrPositionedChildFromBlockLists();
 
     RenderLayer* enclosingFloatPaintingLayer() const;
 
-    virtual int firstLineBoxBaseline() const { return -1; }
+    // if autoBaseline is true, baselineType is ignored and determined from the context

[eseidel, 2015/06/24 23:20:35]

Why not just make it a separate method?  firstLineBoxBaselineFromContext()?

+    virtual int firstLineBoxBaseline(bool autoBaseline = true, FontBaseline baselineType = AlphabeticBaseline) const { return -1; }
     virtual int inlineBlockBaseline(LineDirectionMode) const { return -1; } // Returns -1 if we should skip this box when computing the baseline of an inline-block.
 
     bool isFlexItem() const { return !isInline() && !isFloatingOrOutOfFlowPositioned() && parent() && parent()->isFlexibleBox(); }
 
     virtual LayoutUnit lineHeight(bool firstLine, LineDirectionMode, LinePositionMode = PositionOnContainingLine) const override;
     virtual int baselinePosition(FontBaseline, bool firstLine, LineDirectionMode, LinePositionMode = PositionOnContainingLine) const override;
 
     virtual LayoutUnit offsetLeft() const override;
     virtual LayoutUnit offsetTop() const override;
 
@@ skipping 173 matching lines @@
         if (UNLIKELY(inlineBoxWrapper() != 0))
             deleteLineBoxWrapper();
     }
 
     ensureRareData().m_inlineBoxWrapper = boxWrapper;
 }
 
 } // namespace blink
 
 #endif  // SKY_ENGINE_CORE_RENDERING_RENDERBOX_H_