[webcrypto] Check for empty key usages *after* key creation rather than before, to match the spec's…

components/webcrypto/algorithms/util.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_WEBCRYPTO_ALGORITHMS_UTIL_H_
 #define COMPONENTS_WEBCRYPTO_ALGORITHMS_UTIL_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 34 matching lines @@
 
 // Rounds a bit count (up) to the nearest byte count.
 //
 // This is mathematically equivalent to (x + 7) / 8, however has no
 // possibility of integer overflow.
 template <typename T>
 T NumBitsToBytes(T x) {
   return (x / 8) + (7 + (x % 8)) / 8;
 }
 
-enum class EmptyUsagePolicy {
-  // Allow keys to have empty usages.
-  ALLOW_EMPTY,
-
-  // Do not allow keys to have empty usages.
-  REJECT_EMPTY,
-};
-
 // Verifies whether a key can be created using |actual_usages| when the
 // algorithm supports |all_possible_usages|.
 Status CheckKeyCreationUsages(blink::WebCryptoKeyUsageMask all_possible_usages,
-                              blink::WebCryptoKeyUsageMask actual_usages,
-                              EmptyUsagePolicy empty_usage_policy);
+                              blink::WebCryptoKeyUsageMask actual_usages);
 
 // TODO(eroman): This doesn't really belong in this file. Move it into Blink
 // instead.
 //
 // Returns true if the set bits in b make up a subset of the set bits in a.
 bool ContainsKeyUsages(blink::WebCryptoKeyUsageMask a,
                        blink::WebCryptoKeyUsageMask b);
 
 // Allocates a new BIGNUM given a std::string big-endian representation.
 BIGNUM* CreateBIGNUM(const std::string& n);
@@ skipping 11 matching lines @@
                           const CryptoData& data,
                           unsigned int tag_length_bytes,
                           const CryptoData& iv,
                           const CryptoData& additional_data,
                           const EVP_AEAD* aead_alg,
                           std::vector<uint8_t>* buffer);
 
 }  // namespace webcrypto
 
 #endif  // COMPONENTS_WEBCRYPTO_ALGORITHMS_UTIL_H_