Let CConnection intercept more callbacks

We need more callbacks for correct operation of multi-threaded
rect decoding.
diff --git a/tests/decperf.cxx b/tests/decperf.cxx
index dfd8a90..a200e5b 100644
--- a/tests/decperf.cxx
+++ b/tests/decperf.cxx
@@ -99,11 +99,15 @@
 
 void CConn::framebufferUpdateStart()
 {
+  CConnection::framebufferUpdateStart();
+
   startCpuCounter();
 }
 
 void CConn::framebufferUpdateEnd()
 {
+  CConnection::framebufferUpdateEnd();
+
   endCpuCounter();
 
   cpuTime += getCpuCounter();