Special handling of a rectangular video area in the UpdateTracker and derived/related classes.

git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@2327 3789f03b-4d11-0410-bbf8-ca57d06f2519
diff --git a/common/rfb/VNCServerST.h b/common/rfb/VNCServerST.h
index bc15b7f..37b75ea 100644
--- a/common/rfb/VNCServerST.h
+++ b/common/rfb/VNCServerST.h
@@ -83,6 +83,7 @@
     virtual void serverCutText(const char* str, int len);
     virtual void add_changed(const Region &region);
     virtual void add_copied(const Region &dest, const Point &delta);
+    virtual void set_video_area(const Rect &rect);
     virtual bool clientsReadyForUpdate();
     virtual void tryUpdate();
     virtual void setCursor(int width, int height, const Point& hotspot,