Change string16 to std::string in the gfx::Font() interface.

ui/gfx/platform_font_win.h

Index: ui/gfx/platform_font_win.h
diff --git a/ui/gfx/platform_font_win.h b/ui/gfx/platform_font_win.h
index 56f3340ab43ca236e203a3e5e5b968a7964155b4..c56ff93351d70393c75b4675eaeb0bc495bdd9aa 100644
--- a/ui/gfx/platform_font_win.h
+++ b/ui/gfx/platform_font_win.h
@@ -17,7 +17,7 @@ class UI_EXPORT PlatformFontWin : public PlatformFont {
   PlatformFontWin();
   explicit PlatformFontWin(const Font& other);
   explicit PlatformFontWin(NativeFont native_font);
-  PlatformFontWin(const string16& font_name, int font_size);
+  PlatformFontWin(const std::string& font_name, int font_size);
 
   // Dialog units to pixels conversion.
   // See http://support.microsoft.com/kb/145994 for details.
@@ -48,7 +48,7 @@ class UI_EXPORT PlatformFontWin : public PlatformFont {
   virtual int GetStringWidth(const string16& text) const;
   virtual int GetExpectedTextWidth(int length) const;
   virtual int GetStyle() const;
-  virtual string16 GetFontName() const;
+  virtual std::string GetFontName() const;
   virtual int GetFontSize() const;
   virtual NativeFont GetNativeFont() const;
 
@@ -81,7 +81,7 @@ class UI_EXPORT PlatformFontWin : public PlatformFont {
     int ave_char_width() const { return ave_char_width_; }
     int style() const { return style_; }
     int dlu_base_x() const { return dlu_base_x_; }
-    const string16& font_name() const { return font_name_; }
+    const std::string& font_name() const { return font_name_; }
 
    private:
     friend class  base::RefCounted<HFontRef>;
@@ -95,7 +95,7 @@ class UI_EXPORT PlatformFontWin : public PlatformFont {
     const int style_;
     // Constants used in converting dialog units to pixels.
     const int dlu_base_x_;
-    string16 font_name_;
+    std::string font_name_;
 
     DISALLOW_COPY_AND_ASSIGN(HFontRef);
   };
@@ -104,7 +104,7 @@ class UI_EXPORT PlatformFontWin : public PlatformFont {
   void InitWithCopyOfHFONT(HFONT hfont);
 
   // Initializes this object with the specified font name and size.
-  void InitWithFontNameAndSize(const string16& font_name,
+  void InitWithFontNameAndSize(const std::string& font_name,
                                int font_size);
 
   // Returns the base font ref. This should ONLY be invoked on the