[webcrypto] Add JWK RSA public key export for NSS.

content/child/webcrypto/platform_crypto_nss.cc

Index: content/child/webcrypto/platform_crypto_nss.cc
diff --git a/content/child/webcrypto/platform_crypto_nss.cc b/content/child/webcrypto/platform_crypto_nss.cc
index 478c7aaff73fbb6c873cdcab6465c6de80a146ec..1769c52c73fb7886e2f3b660fd54d3fbc317eab0 100644
--- a/content/child/webcrypto/platform_crypto_nss.cc
+++ b/content/child/webcrypto/platform_crypto_nss.cc
@@ -695,6 +695,29 @@ Status ExportKeySpki(PublicKey* key, blink::WebArrayBuffer* buffer) {
   return Status::Success();
 }
 
+Status ExportRsaPublicKey(PublicKey* key,
+                          std::vector<uint8>* modulus,
+                          std::vector<uint8>* public_exponent) {
+  DCHECK(key);
+  DCHECK(key->key());
+
+  if (key->key()->keyType != rsaKey)
+    return Status::ErrorUnsupported();
+
+  SECItem modulus_item = key->key()->u.rsa.modulus;
+  if (!modulus_item.data || !modulus_item.len)

[eroman, 2014/03/24 22:05:51]

Consider extracting this to a function:

CopySECItemToVector(const SECItem& item, std::vector<uint8>* out);

Then you have:

CopySECItemToVector(key->key()->u.rsa.publicExponent, public_exponent);
CopySECItemToVector(key->key()->u.rsa.modulus, modulus);

if (public_exponent->empty() || modulus->empty())
  return Status::ErrorUnexpected();

[padolph, 2014/03/25 01:10:28]

Done.

+    return Status::ErrorUnexpected();
+
+  SECItem public_exponent_item = key->key()->u.rsa.publicExponent;
+  if (!public_exponent_item.data || !public_exponent_item.len)
+    return Status::ErrorUnexpected();
+
+  modulus->assign(modulus_item.data, modulus_item.data + modulus_item.len);
+  public_exponent->assign(public_exponent_item.data,
+                          public_exponent_item.data + public_exponent_item.len);
+  return Status::Success();
+}
+
 Status ImportKeyPkcs8(const blink::WebCryptoAlgorithm& algorithm,
                       const CryptoData& key_data,
                       bool extractable,