Add histogram to track NPN/ALPN.

net/socket/ssl_client_socket.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/socket/ssl_client_socket.h"
 
 #include "base/metrics/histogram.h"
+#include "base/metrics/sparse_histogram.h"
 #include "base/strings/string_util.h"
 #include "crypto/ec_private_key.h"
 #include "net/base/host_port_pair.h"
 #include "net/ssl/channel_id_service.h"
 #include "net/ssl/ssl_config_service.h"
 
 namespace net {
 
 SSLClientSocket::SSLClientSocket()
     : was_npn_negotiated_(false),
       was_spdy_negotiated_(false),
       protocol_negotiated_(kProtoUnknown),
       channel_id_sent_(false),
       signed_cert_timestamps_received_(false),
-      stapled_ocsp_response_received_(false) {
+      stapled_ocsp_response_received_(false),
+      protocol_negotiation_(PN_UNKNOWN) {
 }
 
 // static
 NextProto SSLClientSocket::NextProtoFromString(
     const std::string& proto_string) {
   if (proto_string == "http1.1" || proto_string == "http/1.1") {
     return kProtoHTTP11;
   } else if (proto_string == "spdy/2") {
     return kProtoDeprecatedSPDY2;
   } else if (proto_string == "spdy/3") {
@@ skipping 192 matching lines @@
     wire_protos.push_back(i->size());
     wire_protos.resize(wire_protos.size() + i->size());
     memcpy(&wire_protos[wire_protos.size() - i->size()],
            i->data(), i->size());
   }
   DCHECK_EQ(wire_protos.size(), wire_length);
 
   return wire_protos;
 }
 
+void SSLClientSocket::RecordProtocolNegotiation() {
+  if (protocol_negotiation_ == PN_UNKNOWN)
+    return;
+  std::string proto;
+  SSLClientSocket::NextProtoStatus status = GetNextProto(&proto);
+  if (status == kNextProtoUnsupported)
+    return;
+  if (status == kNextProtoNoOverlap) {
+    DCHECK(protocol_negotiation_ != PN_ALPN);
+    protocol_negotiation_ = PN_NPN_NO_OVERLAP;
+  }
+  NextProto protocol_negotiated = SSLClientSocket::NextProtoFromString(proto);
+  UMA_HISTOGRAM_SPARSE_SLOWLY(
+      "Net.SSLProtocolNegotiation",
+      static_cast<base::HistogramBase::Sample>(protocol_negotiation_) +
+          static_cast<base::HistogramBase::Sample>(protocol_negotiated));
+}
+
 }  // namespace net