Revert of TextRun::length() should return an unsigned

Source/platform/fonts/Font.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2006, 2007, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Holger Hans Peter Freyther
  *
  * 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 86 matching lines @@
 
     const FontDescription& fontDescription() const { return m_fontDescription; }
 
     void update(PassRefPtrWillBeRawPtr<FontSelector>) const;
 
     enum CustomFontNotReadyAction { DoNotPaintIfFontNotReady, UseFallbackIfFontNotReady };
     float drawText(GraphicsContext*, const TextRunPaintInfo&, const FloatPoint&, CustomFontNotReadyAction = DoNotPaintIfFontNotReady) const;
     void drawEmphasisMarks(GraphicsContext*, const TextRunPaintInfo&, const AtomicString& mark, const FloatPoint&) const;
 
     float width(const TextRun&, HashSet<const SimpleFontData*>* fallbackFonts = 0, GlyphOverflow* = 0) const;
-    float width(const TextRun&, unsigned& charsConsumed, Glyph& glyphId) const;
+    float width(const TextRun&, int& charsConsumed, Glyph& glyphId) const;
 
     int offsetForPosition(const TextRun&, float position, bool includePartialGlyphs) const;
     FloatRect selectionRectForText(const TextRun&, const FloatPoint&, int h, int from = 0, int to = -1, bool accountForGlyphBounds = false) const;
 
     bool isFixedPitch() const;
 
     // Metrics that we query the FontFallbackList for.
     const FontMetrics& fontMetrics() const { return primaryFont()->fontMetrics(); }
     float spaceWidth() const { return primaryFont()->spaceWidth() + fontDescription().letterSpacing(); }
     float tabWidth(const SimpleFontData&, unsigned tabSize, float position) const;
@@ skipping 102 matching lines @@
 {
     if (!tabSize)
         return fontDescription().letterSpacing();
     float tabWidth = tabSize * fontData.spaceWidth() + fontDescription().letterSpacing();
     return tabWidth - fmodf(position, tabWidth);
 }
 
 } // namespace blink
 
 #endif