Uses and returns the fractional width in text eliding

ui/gfx/platform_font_win.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_win.h"
 
 #include <windows.h>
 #include <math.h>
 
 #include <algorithm>
 #include <string>
 
 #include "base/logging.h"
 #include "base/strings/string_util.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/win/scoped_hdc.h"
 #include "base/win/scoped_select_object.h"
 #include "base/win/win_util.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/font.h"
+#include "ui/gfx/font_list.h"
 #include "ui/gfx/win/scoped_set_map_mode.h"
 
 namespace {
 
 // If the tmWeight field of a TEXTMETRIC structure has a value >= this, the
 // font is bold.
 const int kTextMetricWeightBold = 700;
 
 // Returns the minimum font size, using the minimum size callback, if set.
 int GetMinimumFontSize() {
@@ skipping 115 matching lines @@
 
 int PlatformFontWin::GetAverageCharacterWidth() const {
   return font_ref_->ave_char_width();
 }
 
 int PlatformFontWin::GetStringWidth(const base::string16& text) const {
   return Canvas::GetStringWidth(text,
                                 Font(const_cast<PlatformFontWin*>(this)));
 }
 
+float PlatformFontWin::GetStringWidthF(const base::string16& text) const {
+  return Canvas::GetStringWidthF(
+      text, FontList(Font(const_cast<PlatformFontWin*>(this))));
+}
+
 int PlatformFontWin::GetExpectedTextWidth(int length) const {
   return length * std::min(font_ref_->GetDluBaseX(),
                            GetAverageCharacterWidth());
 }
 
 int PlatformFontWin::GetStyle() const {
   return font_ref_->style();
 }
 
 std::string PlatformFontWin::GetFontName() const {
@@ skipping 157 matching lines @@
   return new PlatformFontWin(native_font);
 }
 
 // static
 PlatformFont* PlatformFont::CreateFromNameAndSize(const std::string& font_name,
                                                   int font_size) {
   return new PlatformFontWin(font_name, font_size);
 }
 
 }  // namespace gfx