Change TextRun's length() and charactersLength() to return an unsigned

third_party/WebKit/Source/platform/fonts/shaping/SimpleShaper.cpp

 /*
  * Copyright (C) 2003, 2006, 2008, 2009, 2010, 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 81 matching lines @@
     bool isExpansionOpportunity = Character::treatAsSpace(charData.character) || (m_textRun.getTextJustify() == TextJustifyDistribute);
     if (isExpansionOpportunity || (m_textRun.getTextJustify() == TextJustifyAuto && Character::isCJKIdeographOrSymbol(charData.character))) {
         // Distribute the run's total expansion evenly over all expansion opportunities in the run.
         if (m_expansion) {
             if (!isExpansionOpportunity && !m_isAfterExpansion) {
                 // Take the expansion opportunity before this ideograph.
                 m_expansion -= m_expansionPerOpportunity;
                 m_runWidthSoFar += m_expansionPerOpportunity;
             }
             if (m_textRun.allowsTrailingExpansion()
-                || (m_textRun.ltr() && charData.characterOffset + charData.clusterLength < static_cast<size_t>(m_textRun.length()))
+                || (m_textRun.ltr() && charData.characterOffset + charData.clusterLength < m_textRun.length())
                 || (m_textRun.rtl() && charData.characterOffset)) {
                 m_expansion -= m_expansionPerOpportunity;
                 width += m_expansionPerOpportunity;
                 m_isAfterExpansion = true;
             }
         } else {
             m_isAfterExpansion = false;
         }
 
         // Account for word spacing.
@@ skipping 105 matching lines @@
     float initialWidth = m_runWidthSoFar;
 
     if (!advance(m_currentCharacter + 1))
         return false;
 
     width = m_runWidthSoFar - initialWidth;
     return true;
 }
 
 } // namespace blink