Set OPENSSL_EC_NAMED_CURVE explicitly on EC key so that certificate has ASN1 OID and NIST curve info. Without this openSSL handshake negotiation fails throwing NO_SHARED_CIPHER error. the change made is along the lines of openssl behavior documented here: https://wiki.openssl.org/index.php/Elliptic_Curve_Diffie_Hellman#ECDH_and_Named_Curves

tested with openssl 1.0.2j

BUG=webrtc:6763

Review-Url: https://codereview.webrtc.org/2534773002
Cr-Commit-Position: refs/heads/master@{#15536}
diff --git a/webrtc/base/opensslstreamadapter.cc b/webrtc/base/opensslstreamadapter.cc
index 0e7a292..3b3aa5d 100644
--- a/webrtc/base/opensslstreamadapter.cc
+++ b/webrtc/base/opensslstreamadapter.cc
@@ -20,6 +20,7 @@
 #include <openssl/x509v3.h>
 #ifndef OPENSSL_IS_BORINGSSL
 #include <openssl/dtls1.h>
+#include <openssl/ssl.h>
 #endif
 
 #include <memory>