Add flag to enable immersive fullscreen for v2 apps

ui/views/widget/widget_deletion_observer.h

Index: ui/views/widget/widget_deletion_observer.h
diff --git a/ui/views/widget/widget_deletion_observer.h b/ui/views/widget/widget_deletion_observer.h
index 1956e7f1aec2f47f4a2dae07e49eac8f67276bc8..7182d2dcf4507fb363eb198e4a24629ce25eb7d5 100644
--- a/ui/views/widget/widget_deletion_observer.h
+++ b/ui/views/widget/widget_deletion_observer.h
@@ -7,13 +7,14 @@
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
+#include "ui/views/views_export.h"
 #include "ui/views/widget/widget_observer.h"
 
 namespace views {
 class Widget;
 
 // A simple WidgetObserver that can be probed for the life of a widget.
-class WidgetDeletionObserver : public WidgetObserver {
+class VIEWS_EXPORT WidgetDeletionObserver : public WidgetObserver {
  public:
   explicit WidgetDeletionObserver(Widget* widget);
   virtual ~WidgetDeletionObserver();