Add a new histogram Net.QuicSession.HandshakeConfirmedTime which tracks

the elapsed time between starting the crypto handshake, and receiving
confirmation from the server.

Review URL: https://codereview.chromium.org/318143002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@275654 0039d316-1c4b-4281-b951-d872f2087c98

net/quic/quic_client_session.cc

@@ -435,6 +435,7 @@ bool QuicClientSession::GetSSLInfo(SSLInfo* ssl_info) const {
 int QuicClientSession::CryptoConnect(bool require_confirmation,
                                      const CompletionCallback& callback) {
   require_confirmation_ = require_confirmation;
+  handshake_start_ = base::TimeTicks::Now();
   RecordHandshakeState(STATE_STARTED);
   if (!crypto_stream_->CryptoConnect()) {
     // TODO(wtc): change crypto_stream_.CryptoConnect() to return a
@@ -544,6 +545,8 @@ void QuicClientSession::OnCryptoHandshakeEvent(CryptoHandshakeEvent event) {
     base::ResetAndReturn(&callback_).Run(OK);
   }
   if (event == HANDSHAKE_CONFIRMED) {
+    UMA_HISTOGRAM_TIMES("Net.QuicSession.HandshakeConfirmedTime",
+                        base::TimeTicks::Now() - handshake_start_);
     ObserverSet::iterator it = observers_.begin();
     while (it != observers_.end()) {
       Observer* observer = *it;

net/quic/quic_client_session.h

@@ -15,6 +15,7 @@
 #include "base/basictypes.h"
 #include "base/containers/hash_tables.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/time/time.h"
 #include "net/base/completion_callback.h"
 #include "net/proxy/proxy_server.h"
 #include "net/quic/quic_client_session_base.h"
@@ -235,6 +236,7 @@ class NET_EXPORT_PRIVATE QuicClientSession : public QuicClientSessionBase {
   size_t num_total_streams_;
   base::TaskRunner* task_runner_;
   BoundNetLog net_log_;
+  base::TimeTicks handshake_start_;  // Time the handshake was started.
   QuicConnectionLogger logger_;
   // Number of packets read in the current read loop.
   size_t num_packets_read_;

tools/metrics/histograms/histograms.xml

@@ -14297,6 +14297,14 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Net.QuicSession.HandshakeConfirmedTime" units="Milliseconds">
+  <owner>rch@chromium.org</owner>
+  <summary>
+    The elapsed time between starting the crypto handshake, and receiving
+    confirmation from the server.
+  </summary>
+</histogram>
+
 <histogram name="Net.QuicSession.HandshakeRoundTrips" units="RTTs">
   <obsolete>
     see Net.QuicSession.Connect*PortForHTTP*