diff -r bbf46f59e123 -r 25ffed67c7ef graphicscomposition/openwfcompositionengine/adaptation/include/owfnativestream.h
--- a/graphicscomposition/openwfcompositionengine/adaptation/include/owfnativestream.h	Tue Aug 31 16:31:06 2010 +0300
+++ b/graphicscomposition/openwfcompositionengine/adaptation/include/owfnativestream.h	Wed Sep 01 12:39:21 2010 +0100
@@ -1,5 +1,4 @@
 /* Copyright (c) 2009 The Khronos Group Inc.
- * Portions copyright (c) 2009-2010  Nokia Corporation and/or its subsidiary(-ies)
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and/or associated documentation files (the
@@ -202,6 +201,48 @@
                                   EGLDisplay dpy,
                                   EGLSyncKHR sync);
 
+/*!---------------------------------------------------------------------------
+ *  Register stream content observer (append to chain). The observer will
+ *  receive buffer modification event from the stream whenever a buffer is
+ *  committed.
+ *
+ *  \param stream           Stream handle
+ *  \param observer         Stream observer
+ *  \param data             Optional data to pass to observer callback
+ *                          function when event is dispatched.
+ *----------------------------------------------------------------------------*/
+ OWF_PUBLIC OWF_STREAM_ERROR
+owfNativeStreamAddObserver(OWFNativeStreamType stream,
+                           OWFStreamCallback observer,
+                           void* data);
+
+/*!---------------------------------------------------------------------------
+ *  Remove stream content observer.
+ *
+ *  \param stream           Stream handle
+ *  \param observer         Observer to remove
+ *
+ *  \param Zero if the observer was removed successfully, otherwise non-zero
+ *  (OWF_STREAM_ERROR_INVALID_STREAM if the stream is invalid;
+ *   OWF_STREAM_ERROR_INVALID_OBSERVER if the observer is invalid.)
+ *
+ *   NOTE (khronos bugzilla #5188): "Because the parameter is the observer
+ *   function, it is likely that the wrong context could be removed if
+ *   two contexts sharing the same implementation code are observing the
+ *   same stream, and then one removes its observer. Ideally, both the
+ *   function and the client void* should be passed as parameters
+ *   to uniquely identify the observer."
+ *
+ *   The issue can be fixed by adding sync object handle into the interface
+ *   of this function. Sync object must be passed to the static comparison
+ *   function (ObserversEqual). Implementator must take into account that
+ *   when the stream is destroyed, all observers of that stream must be destroyed.
+ *
+ *----------------------------------------------------------------------------*/
+ OWF_API_CALL OWF_STREAM_ERROR
+owfNativeStreamRemoveObserver(OWFNativeStreamType stream,
+                              OWFStreamCallback observer,
+                              void* data);
 
 /*!---------------------------------------------------------------------------
  *  Enable/disable stream content notifications.