ui/gfx: Use base::string16 now that string16 was moved into base namespace.

ui/gfx/platform_font_ios.mm

 // 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_ios.h"
 
 #import <UIKit/UIKit.h>
 
 #include "base/basictypes.h"
 #include "base/strings/sys_string_conversions.h"
@@ skipping 37 matching lines @@
 }
 
 int PlatformFontIOS::GetBaseline() const {
   return ascent_;
 }
 
 int PlatformFontIOS::GetAverageCharacterWidth() const {
   return average_width_;
 }
 
-int PlatformFontIOS::GetStringWidth(const string16& text) const {
+int PlatformFontIOS::GetStringWidth(const base::string16& text) const {
   NSString* ns_text = base::SysUTF16ToNSString(text);
   return [ns_text sizeWithFont:GetNativeFont()].width;
 }
 
 int PlatformFontIOS::GetExpectedTextWidth(int length) const {
   return length * average_width_;
 }
 
 int PlatformFontIOS::GetStyle() const {
   return style_;
@@ skipping 50 matching lines @@
   return new PlatformFontIOS(native_font);
 }
 
 // static
 PlatformFont* PlatformFont::CreateFromNameAndSize(const std::string& font_name,
                                                   int font_size) {
   return new PlatformFontIOS(font_name, font_size);
 }
 
 }  // namespace gfx