Moves the display reconfiguration callback into a separate class,
so that it can be shared with the cursor monitor when single monitor capturing
is added (https://webrtc-codereview.appspot.com/4679005/).
This Cl should have no functionality change.

BUG=2253
R=henrike@webrtc.org, sergeyu@chromium.org

Review URL: https://webrtc-codereview.appspot.com/7599004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5461 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/system_wrappers/interface/scoped_refptr.h b/webrtc/system_wrappers/interface/scoped_refptr.h
index a8a0074..b344d21 100644
--- a/webrtc/system_wrappers/interface/scoped_refptr.h
+++ b/webrtc/system_wrappers/interface/scoped_refptr.h
@@ -11,6 +11,8 @@
 #ifndef SYSTEM_WRAPPERS_INTERFACE_SCOPED_REFPTR_H_
 #define SYSTEM_WRAPPERS_INTERFACE_SCOPED_REFPTR_H_
 
+#include <stddef.h>
+
 namespace webrtc {
 
 // Extracted from Chromium's src/base/memory/ref_counted.h.