Introduce ui.dll / libui.so for the component build.

ui/gfx/font.h

 // Copyright (c) 2011 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_FONT_H_
 #define UI_GFX_FONT_H_
 #pragma once
 
 #include <string>
 
 #include "base/memory/ref_counted.h"
 #include "base/string16.h"
 #include "ui/gfx/native_widget_types.h"
+#include "ui/ui_api.h"
 
 namespace gfx {
 
 class PlatformFont;
 
 // Font provides a wrapper around an underlying font. Copy and assignment
 // operators are explicitly allowed, and cheap.
-class Font {
+class UI_API Font {
  public:
   // The following constants indicate the font style.
   enum FontStyle {
     NORMAL = 0,
     BOLD = 1,
     ITALIC = 2,
     UNDERLINED = 4,
   };
 
   // Creates a font with the default name and style.
@@ skipping 72 matching lines @@
   PlatformFont* platform_font() const { return platform_font_.get(); }
 
  private:
   // Wrapped platform font implementation.
   scoped_refptr<PlatformFont> platform_font_;
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_FONT_H_