Allow a crypto::RSAPrivateKey object to be wrapped round a pre-existing

crypto/rsa_private_key_openssl.cc

Index: crypto/rsa_private_key_openssl.cc
diff --git a/crypto/rsa_private_key_openssl.cc b/crypto/rsa_private_key_openssl.cc
index 8dcde61628f58b6f83859959c5d933b9c5ae1731..053c4a2f930d1e15fa8a971b41e36b533c2bae8a 100644
--- a/crypto/rsa_private_key_openssl.cc
+++ b/crypto/rsa_private_key_openssl.cc
@@ -98,6 +98,16 @@ RSAPrivateKey* RSAPrivateKey::CreateFromPrivateKeyInfo(
   return result.release();
 }
 
+// static
+RSAPrivateKey* RSAPrivateKey::CreateFromKey(EVP_PKEY* key) {
+  DCHECK(key);
+  if (EVP_PKEY_type(key->type) != EVP_PKEY_RSA)
+    return NULL;
+  RSAPrivateKey* copy = new RSAPrivateKey();
+  copy->key_ = EVP_PKEY_dup(key);
+  return copy;
+}
+
 RSAPrivateKey::RSAPrivateKey()
     : key_(NULL) {
 }