Update SVG text layout to use shaped glyph data & go fast (O(n^2)->O(n))

third_party/WebKit/Source/core/layout/svg/SVGTextMetrics.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
@@ skipping 66 matching lines @@
 
     // We handle letter & word spacing ourselves.
     run.disableSpacing();
 
     // Propagate the maximum length of the characters buffer to the TextRun, even when we're only processing a substring.
     run.setCharactersLength(textLayoutItem.textLength() - position);
     ASSERT(run.charactersLength() >= run.length());
     return run;
 }
 
-SVGTextMetrics SVGTextMetrics::measureCharacterRange(LineLayoutSVGInlineText textLayoutItem, unsigned position, unsigned length, TextDirection textDirection)
-{
-    ASSERT(textLayoutItem);
-    return SVGTextMetrics(textLayoutItem, constructTextRun(textLayoutItem, position, length, textDirection));
-}
-
 SVGTextMetrics::SVGTextMetrics(LineLayoutSVGInlineText textLayoutItem, unsigned length, float width)
 {
     ASSERT(textLayoutItem);
 
     float scalingFactor = textLayoutItem.scalingFactor();
     ASSERT(scalingFactor);
 
     m_width = width / scalingFactor;
     m_height = textLayoutItem.scaledFont().fontMetrics().floatHeight() / scalingFactor;
 
     m_length = length;
 }
 
 float SVGTextMetrics::advance(FontOrientation orientation) const
 {
     switch (orientation) {
     case FontOrientation::Horizontal:
     case FontOrientation::VerticalRotated:
         return width();
     case FontOrientation::VerticalUpright:
         return height();
     default:
         ASSERT_NOT_REACHED();
         return width();
     }
 }
 
 } // namespace blink