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

Source/core/rendering/svg/SVGTextMetricsBuilder.cpp

 /*
  * Copyright (C) Research In Motion Limited 2010-2012. 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.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #include "config.h"
+
 #include "core/rendering/svg/SVGTextMetricsBuilder.h"
 
 #include "core/rendering/svg/RenderSVGInline.h"
 #include "core/rendering/svg/RenderSVGInlineText.h"
 #include "core/rendering/svg/RenderSVGText.h"
 #include "core/rendering/svg/SVGTextMetrics.h"
 #include "platform/fonts/GlyphBuffer.h"
 #include "platform/fonts/shaping/SimpleShaper.h"
 #include "platform/text/BidiCharacterRun.h"
 #include "platform/text/BidiResolver.h"
 #include "platform/text/TextDirection.h"
 #include "platform/text/TextPath.h"
 #include "platform/text/TextRun.h"
 #include "platform/text/TextRunIterator.h"
 #include "wtf/Vector.h"
 
 namespace blink {
 
 class SVGTextMetricsCalculator {
 public:
     SVGTextMetricsCalculator(RenderSVGInlineText*);
     ~SVGTextMetricsCalculator();
 
     SVGTextMetrics computeMetricsForCharacter(unsigned textPosition);
-    unsigned textLength() const { return m_run.charactersLength(); }
+    unsigned textLength() const { return static_cast<unsigned>(m_run.charactersLength()); }
 
     bool characterStartsSurrogatePair(unsigned textPosition) const
     {
         return U16_IS_LEAD(m_run[textPosition]) && textPosition + 1 < textLength() && U16_IS_TRAIL(m_run[textPosition + 1]);
     }
     bool characterIsWhiteSpace(unsigned textPosition) const
     {
         return m_run[textPosition] == ' ';
     }
 
@@ skipping 213 matching lines @@
 }
 
 void SVGTextMetricsBuilder::buildMetricsAndLayoutAttributes(RenderSVGText* textRoot, RenderSVGInlineText* stopAtLeaf, SVGCharacterDataMap& allCharactersMap)
 {
     ASSERT(textRoot);
     MeasureTextData data(&allCharactersMap);
     walkTree(textRoot, stopAtLeaf, &data);
 }
 
 }