Report metrics about negotiated ciphers.

talk/app/webrtc/webrtcsession.cc

Index: talk/app/webrtc/webrtcsession.cc
diff --git a/talk/app/webrtc/webrtcsession.cc b/talk/app/webrtc/webrtcsession.cc
index 5c8b2df754fe8d69dd5928e2a0477e3f2e8e50ab..d3463aecce27fa9d9314222d415ba1391d37e7cc 100644
--- a/talk/app/webrtc/webrtcsession.cc
+++ b/talk/app/webrtc/webrtcsession.cc
@@ -1392,7 +1392,11 @@ void WebRtcSession::OnTransportCompleted(cricket::Transport* transport) {
   SetIceConnectionState(PeerConnectionInterface::kIceConnectionCompleted);
   // Only report once when Ice connection is completed.
   if (old_state != PeerConnectionInterface::kIceConnectionCompleted) {
-    ReportBestConnectionState(transport);
+    cricket::TransportStats stats;
+    if (metrics_observer_ && transport->GetStats(&stats)) {
+      ReportBestConnectionState(stats);
+      ReportNegotiatedCiphers(stats);
+    }
   }
 }
 
@@ -1872,16 +1876,9 @@ bool WebRtcSession::ReadyToUseRemoteCandidate(
 
 // Walk through the ConnectionInfos to gather best connection usage
 // for IPv4 and IPv6.
-void WebRtcSession::ReportBestConnectionState(cricket::Transport* transport) {
-  if (!metrics_observer_) {
-    return;
-  }
-
-  cricket::TransportStats stats;
-  if (!transport->GetStats(&stats)) {
-    return;
-  }
-
+void WebRtcSession::ReportBestConnectionState(
+    const cricket::TransportStats& stats) {
+  ASSERT(metrics_observer_ != NULL);
   for (cricket::TransportChannelStatsList::const_iterator it =
          stats.channel_stats.begin();
        it != stats.channel_stats.end(); ++it) {
@@ -1904,4 +1901,41 @@ void WebRtcSession::ReportBestConnectionState(cricket::Transport* transport) {
   }
 }
 
+void WebRtcSession::ReportNegotiatedCiphers(
+    const cricket::TransportStats& stats) {
+  ASSERT(metrics_observer_ != NULL);
+  if (!dtls_enabled_ || stats.channel_stats.empty()) {
+    return;
+  }
+
+  const std::string& srtp_cipher = stats.channel_stats[0].srtp_cipher;
+  const std::string& ssl_cipher = stats.channel_stats[0].ssl_cipher;
+  if (srtp_cipher.empty() && ssl_cipher.empty()) {
+    return;
+  }
+
+  PeerConnectionMetricsName srtp_name;
+  PeerConnectionMetricsName ssl_name;
+  if (stats.content_name == cricket::CN_AUDIO) {
+    srtp_name = kAudioSrtpCipher;
+    ssl_name = kAudioSslCipher;
+  } else if (stats.content_name == cricket::CN_VIDEO) {
+    srtp_name = kVideoSrtpCipher;
+    ssl_name = kVideoSslCipher;
+  } else if (stats.content_name == cricket::CN_DATA) {
+    srtp_name = kDataSrtpCipher;
+    ssl_name = kDataSslCipher;
+  } else {
+    ASSERT(false);
+    return;
+  }
+
+  if (!srtp_cipher.empty()) {
+    metrics_observer_->AddHistogramSample(srtp_name, srtp_cipher);
+  }
+  if (!ssl_cipher.empty()) {
+    metrics_observer_->AddHistogramSample(ssl_name, ssl_cipher);
+  }
+}
+
 }  // namespace webrtc