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

sky/engine/core/rendering/RenderBlock.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 198 matching lines @@
 
     virtual void paint(PaintInfo&, const LayoutPoint&, Vector<RenderBox*>& layers) override;
     void paintObject(PaintInfo&, const LayoutPoint&, Vector<RenderBox*>& layers);
     virtual void paintChildren(PaintInfo&, const LayoutPoint&, Vector<RenderBox*>& layers);
 
     virtual void adjustInlineDirectionLineBounds(unsigned /* expansionOpportunityCount */, float& /* logicalLeft */, float& /* logicalWidth */) const { }
 
     virtual void computeIntrinsicLogicalWidths(LayoutUnit& minLogicalWidth, LayoutUnit& maxLogicalWidth) const override;
     virtual void computePreferredLogicalWidths() override;
 
-    virtual int firstLineBoxBaseline() const override;
+    virtual int firstLineBoxBaseline(bool autoBaseline = true, FontBaseline baselineType = AlphabeticBaseline) const override;

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

There is no need to make these params optional.  I'm shocked the compiler lets
you do this.  Which method is it supposed to call when you do
firstLineBoxBaseline()!

     virtual int inlineBlockBaseline(LineDirectionMode) const override;
     virtual int lastLineBoxBaseline(LineDirectionMode) const;
 
     virtual void updateHitTestResult(HitTestResult&, const LayoutPoint&) override;
 
     virtual void styleWillChange(StyleDifference, const RenderStyle& newStyle) override;
     virtual void styleDidChange(StyleDifference, const RenderStyle* oldStyle) override;
 
     virtual bool hasLineIfEmpty() const;
 
@@ skipping 75 matching lines @@
     // FIXME: This is temporary as we move code that accesses block flow
     // member variables out of RenderBlock and into RenderParagraph.
     friend class RenderParagraph;
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderBlock, isRenderBlock());
 
 } // namespace blink
 
 #endif  // SKY_ENGINE_CORE_RENDERING_RENDERBLOCK_H_