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

ui/gfx/size.h

 // 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.
 
 #ifndef UI_GFX_SIZE_H_
 #define UI_GFX_SIZE_H_
 #pragma once
 
+#include <iosfwd>
+
 #include "build/build_config.h"
-
-#include <iosfwd>
+#include "ui/ui_api.h"
 
 #if defined(OS_WIN)
 typedef struct tagSIZE SIZE;
 #elif defined(OS_MACOSX)
 #include <ApplicationServices/ApplicationServices.h>
 #endif
 
 namespace gfx {
 
 // A size has width and height values.
-class Size {
+class UI_API Size {
  public:
   Size() : width_(0), height_(0) {}
   Size(int width, int height);
 #if defined(OS_MACOSX)
   explicit Size(const CGSize& s);
 #endif
 
   ~Size() {}
 
 #if defined(OS_MACOSX)
@@ skipping 35 matching lines @@
   SIZE ToSIZE() const;
 #elif defined(OS_MACOSX)
   CGSize ToCGSize() const;
 #endif
 
  private:
   int width_;
   int height_;
 };
 
-std::ostream& operator<<(std::ostream& out, const gfx::Size& s);
+UI_API std::ostream& operator<<(std::ostream& out, const gfx::Size& s);
 
 }  // namespace gfx
 
 #endif  // UI_GFX_SIZE_H_