Uses and returns the fractional width in text eliding

ui/gfx/canvas.h

 // 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.
 
 #ifndef UI_GFX_CANVAS_H_
 #define UI_GFX_CANVAS_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 121 matching lines @@
                             int line_height,
                             int flags);
   // Obsolete version.  Use the above version which takes FontList.
   static void SizeStringInt(const base::string16& text,
                             const Font& font,
                             int* width,
                             int* height,
                             int line_height,
                             int flags);
 
+  // This is same as SizeStringInt except that fractional size is returned.
+  // See comment in GetStringWidthF for its usage.
+  static void SizeStringFloat(const base::string16& text,
+                              const FontList& font_list,
+                              float* width,
+                              float* height,
+                              int line_height,
+                              int flags);
+
   // Returns the number of horizontal pixels needed to display the specified
   // |text| with |font_list|.
   static int GetStringWidth(const base::string16& text,
                             const FontList& font_list);
   // Obsolete version.  Use the above version which takes FontList.
   static int GetStringWidth(const base::string16& text, const Font& font);
 
+  // This is same as GetStringWidth except that fractional width is returned.
+  // Use this method for the scenario that multiple string widths need to be
+  // summed up. This is because GetStringWidth returns the ceiled width and
+  // adding multiple ceiled widths could cause more precision loss for certain
+  // platform like Mac where the fractioal width is used.
+  static float GetStringWidthF(const base::string16& text,
+                               const FontList& font_list);
+
   // Returns the default text alignment to be used when drawing text on a
   // Canvas based on the directionality of the system locale language.
   // This function is used by Canvas::DrawStringInt when the text alignment
   // is not specified.
   //
   // This function returns either Canvas::TEXT_ALIGN_LEFT or
   // Canvas::TEXT_ALIGN_RIGHT.
   static int DefaultCanvasTextAlignment();
 
   // Draws text with a 1-pixel halo around it of the given color.
@@ skipping 319 matching lines @@
 
   skia::RefPtr<skia::PlatformCanvas> owned_canvas_;
   SkCanvas* canvas_;
 
   DISALLOW_COPY_AND_ASSIGN(Canvas);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_CANVAS_H_