Uses and returns the fractional width in text eliding

ui/gfx/platform_font_pango.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gfx/platform_font_pango.h"
 
 #include <fontconfig/fontconfig.h>
 #include <pango/pango.h>
 
 #include <algorithm>
 #include <string>
 
 #include "base/logging.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/string_split.h"
 #include "base/strings/utf_string_conversions.h"
 #include "third_party/skia/include/core/SkPaint.h"
 #include "third_party/skia/include/core/SkTypeface.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/font.h"
+#include "ui/gfx/font_list.h"
 #include "ui/gfx/pango_util.h"
 
 #if defined(TOOLKIT_GTK)
 #include <gdk/gdk.h>
 #include <gtk/gtk.h>
 #endif
 
 namespace {
 
 // The font family name which is used when a user's application font for
@@ skipping 164 matching lines @@
 int PlatformFontPango::GetAverageCharacterWidth() const {
   const_cast<PlatformFontPango*>(this)->InitPangoMetrics();
   return SkScalarRound(average_width_pixels_);
 }
 
 int PlatformFontPango::GetStringWidth(const base::string16& text) const {
   return Canvas::GetStringWidth(text,
                                 Font(const_cast<PlatformFontPango*>(this)));
 }
 
+float PlatformFontPango::GetStringWidthF(const base::string16& text) const {
+  return Canvas::GetStringWidthF(
+      text, FontList(Font(const_cast<PlatformFontPango*>(this))));
+}
+
 int PlatformFontPango::GetExpectedTextWidth(int length) const {
   double char_width = const_cast<PlatformFontPango*>(this)->GetAverageWidth();
   return round(static_cast<float>(length) * char_width);
 }
 
 int PlatformFontPango::GetStyle() const {
   return style_;
 }
 
 std::string PlatformFontPango::GetFontName() const {
@@ skipping 194 matching lines @@
   return new PlatformFontPango(native_font);
 }
 
 // static
 PlatformFont* PlatformFont::CreateFromNameAndSize(const std::string& font_name,
                                                   int font_size) {
   return new PlatformFontPango(font_name, font_size);
 }
 
 }  // namespace gfx