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

ui/gfx/gtk_preserve_window.h

 // Copyright (c) 2009 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_GTK_PRESERVE_WINDOW_H_
 #define UI_GFX_GTK_PRESERVE_WINDOW_H_
 #pragma once
 
 #include <gdk/gdk.h>
 #include <gtk/gtk.h>
 
+#include "ui/ui_api.h"
+
 // GtkFixed creates an X window when realized and destroys an X window
 // when unrealized. GtkPreserveWindow allows overrides this
 // behaviour. When preserve is set (via gtk_preserve_window_set_preserve),
 // the X window is only destroyed when the widget is destroyed.
 
 G_BEGIN_DECLS
 
 #define GTK_TYPE_PRESERVE_WINDOW                                 \
     (gtk_preserve_window_get_type())
 #define GTK_PRESERVE_WINDOW(obj)                                 \
@@ skipping 16 matching lines @@
 struct _GtkPreserveWindow {
   // Parent class.
   GtkFixed fixed;
 };
 
 struct _GtkPreserveWindowClass {
   GtkFixedClass parent_class;
 };
 
 GType gtk_preserve_window_get_type() G_GNUC_CONST;
-GtkWidget* gtk_preserve_window_new();
+UI_API GtkWidget* gtk_preserve_window_new();
 
 // Whether or not we should preserve associated windows as the widget
 // is realized or unrealized.
 gboolean gtk_preserve_window_get_preserve(GtkPreserveWindow* widget);
 void gtk_preserve_window_set_preserve(GtkPreserveWindow* widget,
                                       gboolean value);
 
 // Whether or not someone else will gdk_window_resize the GdkWindow associated
 // with this widget (needed by the GPU process to synchronize resizing
 // with swapped between front and back buffer).
-void gtk_preserve_window_delegate_resize(GtkPreserveWindow* widget,
-                                         gboolean delegate);
+UI_API void gtk_preserve_window_delegate_resize(GtkPreserveWindow* widget,
+                                                gboolean delegate);
 
 G_END_DECLS
 
 #endif  // UI_GFX_GTK_PRESERVE_WINDOW_H_