mac: Use NSWidth() and friends in a few more places.

ui/gfx/platform_font_mac.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_mac.h"
 
 #include <Cocoa/Cocoa.h>
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_nsobject.h"
@@ skipping 89 matching lines @@
   CalculateMetrics();
 }
 
 void PlatformFontMac::CalculateMetrics() {
   NSFont* font = GetNativeFont();
   scoped_nsobject<NSLayoutManager> layout_manager(
       [[NSLayoutManager alloc] init]);
   height_ = [layout_manager defaultLineHeightForFont:font];
   ascent_ = [font ascender];
   average_width_ =
-      [font boundingRectForGlyph:[font glyphWithName:@"x"]].size.width;
+      NSWidth([font boundingRectForGlyph:[font glyphWithName:@"x"]]);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // PlatformFont, public:
 
 // static
 PlatformFont* PlatformFont::CreateDefault() {
   return new PlatformFontMac;
 }
 
 // static
 PlatformFont* PlatformFont::CreateFromNativeFont(NativeFont native_font) {
   return new PlatformFontMac(native_font);
 }
 
 // static
 PlatformFont* PlatformFont::CreateFromNameAndSize(const std::string& font_name,
                                                   int font_size) {
   return new PlatformFontMac(font_name, font_size);
 }
 
 }  // namespace gfx