Report decode and render latency for Chromoting

Uses RunningAverage to record these numbers, added JS interface for reporting.

BUG=None
TEST=None

Review URL: http://codereview.chromium.org/6767002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@80515 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 20 insertions, 3 deletions

diff --git a/remoting/client/chromoting_client.cc b/remoting/client/chromoting_client.cc
index bf1ad39..cdfd4ab 100644
--- a/remoting/client/chromoting_client.cc
+++ b/remoting/client/chromoting_client.cc
@@ -154,8 +154,16 @@ void ChromotingClient::DispatchPacket() {
   packet_being_processed_ = true;
 
   ScopedTracer tracer("Handle video packet");
+
+  // Measure the latency between the last packet being received and presented.
+  bool last_packet = (packet->flags() & VideoPacket::LAST_PACKET) != 0;
+  base::Time decode_start;
+  if (last_packet)
+    decode_start = base::Time::Now();
+
   rectangle_decoder_->DecodePacket(
-      packet, NewTracedMethod(this, &ChromotingClient::OnPacketDone));
+      packet, NewTracedMethod(this, &ChromotingClient::OnPacketDone,
+                              last_packet, decode_start));
 }
 
 void ChromotingClient::OnConnectionOpened(protocol::ConnectionToHost* conn) {
@@ -194,22 +202,31 @@ void ChromotingClient::SetConnectionState(ConnectionState s) {
   Repaint();
 }
 
-void ChromotingClient::OnPacketDone() {
+void ChromotingClient::OnPacketDone(bool last_packet,
+                                    base::Time decode_start) {
   if (message_loop() != MessageLoop::current()) {
     message_loop()->PostTask(
         FROM_HERE,
-        NewTracedMethod(this, &ChromotingClient::OnPacketDone));
+        NewTracedMethod(this, &ChromotingClient::OnPacketDone,
+                        last_packet, decode_start));
     return;
   }
 
   TraceContext::tracer()->PrintString("Packet done");
 
+  // Record the latency between the last packet being received and presented.
+  if (last_packet) {
+    stats_.video_decode()->Record(
+        (base::Time::Now() - decode_start).InMilliseconds());
+  }
+
   received_packets_.front().done->Run();
   delete received_packets_.front().done;
   received_packets_.pop_front();
 
   packet_being_processed_ = false;
 
+  // Process the next video packet.
   DispatchPacket();
 }