Add histogram to track NPN/ALPN.

net/socket/ssl_client_socket_pool.cc

Index: net/socket/ssl_client_socket_pool.cc
diff --git a/net/socket/ssl_client_socket_pool.cc b/net/socket/ssl_client_socket_pool.cc
index 388e3fe97a0ef3217dbd0369f4c4a11f1c404295..f71df141d0ef1a5d55cf80cea73d747ffbc99154 100644
--- a/net/socket/ssl_client_socket_pool.cc
+++ b/net/socket/ssl_client_socket_pool.cc
@@ -452,8 +452,10 @@ int SSLConnectJob::DoSSLConnectComplete(int result) {
   // GetNextProto will fail and and trigger a NOTREACHED if we pass in a socket
   // that hasn't had SSL_ImportFD called on it. If we get a certificate error
   // here, then we know that we called SSL_ImportFD.
-  if (result == OK || IsCertificateError(result))
+  if (result == OK || IsCertificateError(result)) {
     status = ssl_socket_->GetNextProto(&proto);
+    ssl_socket_->RecordProtocolNegotiation();
+  }
 
   // If we want spdy over npn, make sure it succeeded.
   if (status == SSLClientSocket::kNextProtoNegotiated) {