Check that usage isn't empty when generateKey() is called

content/child/webcrypto/nss/rsa_key_nss.cc

Index: content/child/webcrypto/nss/rsa_key_nss.cc
diff --git a/content/child/webcrypto/nss/rsa_key_nss.cc b/content/child/webcrypto/nss/rsa_key_nss.cc
index 1cbf6b0d806532c9fcd1569e5dd49f9d4756e349..7a35593c18bdd75b2bfd5d7cd6e29704aa5f069b 100644
--- a/content/child/webcrypto/nss/rsa_key_nss.cc
+++ b/content/child/webcrypto/nss/rsa_key_nss.cc
@@ -513,6 +513,9 @@ Status RsaHashedAlgorithm::GenerateKey(
   const blink::WebCryptoKeyUsageMask private_usages =
       combined_usages & all_private_key_usages_;
 
+  if (private_usages == 0)
+    return Status::ErrorCreateKeyEmptyUsages();
+
   unsigned int public_exponent = 0;
   unsigned int modulus_length_bits = 0;
   status = GetRsaKeyGenParameters(algorithm.rsaHashedKeyGenParams(),