Expose OpenSSL's key_exchange_info in the content API

net/ssl/ssl_cipher_suite_names.cc

Index: net/ssl/ssl_cipher_suite_names.cc
diff --git a/net/ssl/ssl_cipher_suite_names.cc b/net/ssl/ssl_cipher_suite_names.cc
index 271ccdfd90f7d6ef6116e99a625556d5f9fe94fd..0b21edb521778994056e70e9ddf83db3913c0627 100644
--- a/net/ssl/ssl_cipher_suite_names.cc
+++ b/net/ssl/ssl_cipher_suite_names.cc
@@ -4,6 +4,9 @@
 
 #include "net/ssl/ssl_cipher_suite_names.h"
 
+#if defined(USE_OPENSSL)
+#include <openssl/ssl.h>
+#endif
 #include <stdlib.h>
 
 #include "base/logging.h"
@@ -419,4 +422,22 @@ bool IsFalseStartableTLSCipherSuite(uint16 cipher_suite) {
   return true;
 }
 
+const char* ECCurveName(uint16 cipher_suite, int key_exchange_info) {
+#if defined(USE_OPENSSL)
+  int key_exchange, cipher, mac;
+  if (!GetCipherProperties(cipher_suite, &key_exchange, &cipher, &mac))
+    return nullptr;
+  switch (key_exchange) {
+    case 14:  // ECDHE_ECDSA
+    case 16:  // ECDHE_RSA
+      break;
+    default:
+      return nullptr;
+  }
+  return SSL_get_curve_name(key_exchange_info);
+#else
+  return nullptr;
+#endif
+}
+
 }  // namespace net