Report video and network stats averaged over 1s, and create corresponding UMA metrics.

remoting/client/chromoting_stats.cc

Index: remoting/client/chromoting_stats.cc
diff --git a/remoting/client/chromoting_stats.cc b/remoting/client/chromoting_stats.cc
index 71b7199ff5adca1f9222636bb5cc5fe79efedea8..4e0ba49a050a5ce82634da988121e5694e316223 100644
--- a/remoting/client/chromoting_stats.cc
+++ b/remoting/client/chromoting_stats.cc
@@ -7,7 +7,9 @@
 namespace {
 
 // The default window of bandwidth and frame rate in seconds.
-const int kTimeWindow = 3;
+// Set to 60s, so that we average at 60s intervals, same as the rate at which we

[Sergey Ulanov, 2015/06/19 23:08:42]

Actually ChromotingInstance::SendPerfStats() is called once per second. The
webapp logs the values only every 60 seconds, but UI is updated once per second.
UMA stats are aggregated on the client so we can report them more often than
once a minute. I think you can just add another counter in ChromotingStats for
frame rate with 1 second averages and keep existing counter at 3 second window.

[anandc, 2015/06/20 01:31:32]

OK. Created rate counters for fps and bytes/sec, and running-average counters
for encode, capture and round-drip latency.
It seems cleaner to create separate structs containing metrics calculated for
different time-windows. Maybe do that in a follow-up CL?

+// log stats.
+const int kTimeWindow = 60;

[Sergey Ulanov, 2015/06/19 23:08:42]

I don't think we want to changed that - it's useful to have more fine-grained
value in the client UI. 

[anandc, 2015/06/20 01:31:32]

Done.

 
 // We take the last 10 latency numbers and report the average.
 const int kLatencyWindow = 10;