1 files changed, 2 insertions, 1 deletions
diff --git a/ui/base/animation/tween.h b/ui/base/animation/tween.h
index 873281f..9681bed 100644
--- a/ui/base/animation/tween.h
+++ b/ui/base/animation/tween.h
@@ -7,6 +7,7 @@
 #pragma once
 
 #include "base/basictypes.h"
+#include "ui/ui_api.h"
 
 namespace gfx {
 class Rect;
@@ -14,7 +15,7 @@ class Rect;
 
 namespace ui {
 
-class Tween {
+class UI_API Tween {
  public:
   enum Type {
     LINEAR,        // Linear.