Rework gfx::Font by moving platform-specific code into inner classes....

gfx/font_mac.mm

-// Copyright (c) 2010 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 "gfx/font.h"
-
-#include <Cocoa/Cocoa.h>
-
-#include "base/logging.h"
-#include "base/scoped_nsobject.h"
-#include "base/sys_string_conversions.h"
-#include "gfx/canvas_skia.h"
-
-namespace gfx {
-
-// static
-Font Font::CreateFont(const std::wstring& font_name, int font_size) {
-  return Font(font_name, font_size, NORMAL);
-}
-
-Font::Font(const std::wstring& font_name, int font_size, int style)
-    : font_name_(font_name),
-      font_size_(font_size),
-      style_(style) {
-  calculateMetrics();
-}
-
-Font::Font()
-    : font_size_([NSFont systemFontSize]),
-      style_(NORMAL) {
-  NSFont* system_font = [NSFont systemFontOfSize:font_size_];
-  font_name_ = base::SysNSStringToWide([system_font fontName]);
-  calculateMetrics();
-}
-
-void Font::calculateMetrics() {
-  NSFont* font = nativeFont();
-  scoped_nsobject<NSLayoutManager> layout_manager(
-      [[NSLayoutManager alloc] init]);
-  height_ = [layout_manager defaultLineHeightForFont:font];
-  ascent_ = [font ascender];
-  avg_width_ = [font boundingRectForGlyph:[font glyphWithName:@"x"]].size.width;
-}
-
-Font Font::DeriveFont(int size_delta, int style) const {
-  return Font(font_name_, font_size_ + size_delta, style);
-}
-
-int Font::height() const {
-  return height_;
-}
-
-int Font::baseline() const {
-  return ascent_;
-}
-
-int Font::ave_char_width() const {
-  return avg_width_;
-}
-
-int Font::GetStringWidth(const std::wstring& text) const {
-  int width = 0, height = 0;
-  CanvasSkia::SizeStringInt(text, *this, &width, &height,
-                            gfx::Canvas::NO_ELLIPSIS);
-  return width;
-}
-
-int Font::GetExpectedTextWidth(int length) const {
-  return length * avg_width_;
-}
-
-int Font::style() const {
-  return style_;
-}
-
-const std::wstring& Font::FontName() const {
-  return font_name_;
-}
-
-int Font::FontSize() {
-  return font_size_;
-}
-
-NativeFont Font::nativeFont() const {
-  // TODO(pinkerton): apply |style_| to font. http://crbug.com/34667
-  // We could cache this, but then we'd have to conditionally change the
-  // dtor just for MacOS. Not sure if we want to/need to do that.
-  return [NSFont fontWithName:base::SysWideToNSString(font_name_)
-                         size:font_size_];
-}
-
-}  // namespace gfx