Implement RSAPrivateKey::Copy()

crypto/rsa_private_key_win.cc

Index: crypto/rsa_private_key_win.cc
diff --git a/crypto/rsa_private_key_win.cc b/crypto/rsa_private_key_win.cc
index f7363422db8b18928e95c8b2bd98690a0bc7f3d4..d87c1ec058a79f849b22bc33482842c85d67d2ca 100644
--- a/crypto/rsa_private_key_win.cc
+++ b/crypto/rsa_private_key_win.cc
@@ -134,7 +134,19 @@ bool RSAPrivateKey::InitProvider() {
                                       PROV_RSA_FULL, CRYPT_VERIFYCONTEXT);
 }
 
-bool RSAPrivateKey::ExportPrivateKey(std::vector<uint8>* output) {
+RSAPrivateKey* RSAPrivateKey::Copy() const {
+  scoped_ptr<RSAPrivateKey> copy(new RSAPrivateKey());
+  if (!CryptContextAddRef(provider_, NULL, 0)) {
+    NOTREACHED();
+    return NULL;
+  }
+  copy->provider_.reset(provider_.get());
+  if (!CryptDuplicateKey(key_.get(), NULL, 0, copy->key_.receive()))
+    return NULL;
+  return copy.release();
+}
+
+bool RSAPrivateKey::ExportPrivateKey(std::vector<uint8>* output) const {
   // Export the key
   DWORD blob_length = 0;
   if (!CryptExportKey(key_, 0, PRIVATEKEYBLOB, 0, NULL, &blob_length)) {
@@ -187,7 +199,7 @@ bool RSAPrivateKey::ExportPrivateKey(std::vector<uint8>* output) {
   return pki.Export(output);
 }
 
-bool RSAPrivateKey::ExportPublicKey(std::vector<uint8>* output) {
+bool RSAPrivateKey::ExportPublicKey(std::vector<uint8>* output) const {
   DWORD key_info_len;
   if (!CryptExportPublicKeyInfo(
       provider_, AT_SIGNATURE, X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,