prune down content_dll change to just the CONTENT_EXPORTS

content/common/notification_observer.h

Index: content/common/notification_observer.h
diff --git a/content/common/notification_observer.h b/content/common/notification_observer.h
index 49f74de21f7aabe5308f027aef36aac5b3dfef12..5fa0cb999298c36527fdd1972c911d4e2ff17977 100644
--- a/content/common/notification_observer.h
+++ b/content/common/notification_observer.h
@@ -6,12 +6,14 @@
 #define CONTENT_COMMON_NOTIFICATION_OBSERVER_H_
 #pragma once
 
+#include "content/common/content_export.h"
+
 class NotificationDetails;
 class NotificationSource;
 
 // This is the base class for notification observers. When a matching
 // notification is posted to the notification service, Observe is called.
-class NotificationObserver {
+class CONTENT_EXPORT NotificationObserver {
  public:
   NotificationObserver();
   virtual ~NotificationObserver();