Implement Harmony typography spec.

ui/gfx/platform_font.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_PLATFORM_FONT_H_
 #define UI_GFX_PLATFORM_FONT_H_
 
 #include <string>
 
 #include "base/memory/ref_counted.h"
 #include "base/strings/string16.h"
 #include "build/build_config.h"
 #include "ui/gfx/font.h"
 #include "ui/gfx/gfx_export.h"
 #include "ui/gfx/native_widget_types.h"
 
 namespace gfx {
 
 class Font;
 struct FontRenderParams;
 
 class GFX_EXPORT PlatformFont : public base::RefCounted<PlatformFont> {
  public:
+// The size of the font returned by CreateDefault() on a "default" platform
+// configuration. This allows UI that wants to target a particular size of font
+// to obtain that size for the majority of users, while still compensating for a
+// user preference for a larger or smaller font.
+#if defined(OS_MACOSX)
+  static constexpr int kPopularDefaultFontSize = 13;

[Peter Kasting, 2017/04/06 06:17:07]

Nit: I have no idea where the word "popular" in this name comes from.  Maybe
kDefaultFontSize or kDefaultBaseFontSize or something.

[tapted, 2017/04/06 09:11:10]

heh, that was to try to distinguish it from "CreateDefault()" -- I didn't want
to imply that CreateDefault() is expected to return a font of kDefaultFontSize.
But I guess they are still related - I went for kDefaultBaseFontSize.

+#else
+  static constexpr int kPopularDefaultFontSize = 12;
+#endif
+
   // Creates an appropriate PlatformFont implementation.
   static PlatformFont* CreateDefault();
 #if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_IOS)
   static PlatformFont* CreateFromNativeFont(NativeFont native_font);
 #endif
   // Creates a PlatformFont implementation with the specified |font_name|
   // (encoded in UTF-8) and |font_size| in pixels.
   static PlatformFont* CreateFromNameAndSize(const std::string& font_name,
                                              int font_size);
 
@@ skipping 50 matching lines @@
  protected:
   virtual ~PlatformFont() {}
 
  private:
   friend class base::RefCounted<PlatformFont>;
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_PLATFORM_FONT_H_