Refactor the interface for generating keys.

content/child/webcrypto/nss/aes_key_nss.cc

Index: content/child/webcrypto/nss/aes_key_nss.cc
diff --git a/content/child/webcrypto/nss/aes_key_nss.cc b/content/child/webcrypto/nss/aes_key_nss.cc
index a4a742a1d2c0745ca8fb091c5b2336604f5be15c..dda4d6bd89b8739f226dfb0784c947e240edc509 100644
--- a/content/child/webcrypto/nss/aes_key_nss.cc
+++ b/content/child/webcrypto/nss/aes_key_nss.cc
@@ -38,19 +38,16 @@ AesAlgorithm::AesAlgorithm(CK_MECHANISM_TYPE import_mechanism,
       jwk_suffix_(jwk_suffix) {
 }
 
-Status AesAlgorithm::VerifyKeyUsagesBeforeGenerateKey(
-    blink::WebCryptoKeyUsageMask usage_mask) const {
-  return CheckKeyCreationUsages(all_key_usages_, usage_mask);
-}
+Status AesAlgorithm::GenerateKey(const blink::WebCryptoAlgorithm& algorithm,
+                                 bool extractable,
+                                 blink::WebCryptoKeyUsageMask usage_mask,
+                                 GenerateKeyResult* result) const {
+  Status status = CheckKeyCreationUsages(all_key_usages_, usage_mask);
+  if (status.IsError())
+    return status;
 
-Status AesAlgorithm::GenerateSecretKey(
-    const blink::WebCryptoAlgorithm& algorithm,
-    bool extractable,
-    blink::WebCryptoKeyUsageMask usage_mask,
-    blink::WebCryptoKey* key) const {
   unsigned int keylen_bits;
-  Status status =
-      GetAesKeyGenLengthInBits(algorithm.aesKeyGenParams(), &keylen_bits);
+  status = GetAesKeyGenLengthInBits(algorithm.aesKeyGenParams(), &keylen_bits);
   if (status.IsError())
     return status;
 
@@ -60,7 +57,7 @@ Status AesAlgorithm::GenerateSecretKey(
       usage_mask,
       keylen_bits / 8,
       CKM_AES_KEY_GEN,
-      key);
+      result);
 }
 
 Status AesAlgorithm::VerifyKeyUsagesBeforeImportKey(