Change SimpleShaper::advance to take unsigned

Source/platform/fonts/SimpleShaper.h

 /*
  * Copyright (C) 2003, 2006, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Holger Hans Peter Freyther
  * Copyright (C) 2014 Google 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 25 matching lines @@
 class GlyphBuffer;
 class SimpleFontData;
 class TextRun;
 struct GlyphData;
 
 struct PLATFORM_EXPORT SimpleShaper {
     WTF_MAKE_FAST_ALLOCATED;
 public:
     SimpleShaper(const Font*, const TextRun&, HashSet<const SimpleFontData*>* fallbackFonts = 0, bool accountForGlyphBounds = false, bool forTextEmphasis = false);
 
-    unsigned advance(int to, GlyphBuffer* = 0);
+    unsigned advance(unsigned to, GlyphBuffer* = 0);
     bool advanceOneCharacter(float& width);
 
     float maxGlyphBoundingBoxY() const { ASSERT(m_accountForGlyphBounds); return m_maxGlyphBoundingBoxY; }
     float minGlyphBoundingBoxY() const { ASSERT(m_accountForGlyphBounds); return m_minGlyphBoundingBoxY; }
     float firstGlyphOverflow() const { ASSERT(m_accountForGlyphBounds); return m_firstGlyphOverflow; }
     float lastGlyphOverflow() const { ASSERT(m_accountForGlyphBounds); return m_lastGlyphOverflow; }
 
     const TextRun& run() const { return m_run; }
     float runWidthSoFar() const { return m_runWidthSoFar; }
     unsigned currentOffset() { return m_currentCharacter; }
@@ skipping 38 matching lines @@
     float m_firstGlyphOverflow;
     float m_lastGlyphOverflow;
 
     bool m_accountForGlyphBounds : 1;
     bool m_forTextEmphasis : 1;
 };
 
 } // namespace blink
 
 #endif