[webcryto] Validate key usages during key creation.

content/child/webcrypto/jwk.cc

 // 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.
 
 #include "jwk.h"
 
 #include <algorithm>
 #include <functional>
 #include <map>
 
@@ skipping 432 matching lines @@
   if (!dict->Get(path, &value))
     return Status::Success();
 
   if (!value->GetAsBoolean(result))
     return Status::ErrorJwkPropertyWrongType(path, "boolean");
 
   *property_exists = true;
   return Status::Success();
 }
 
-// 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) {
-  return (a & b) == b;
-}
-
 // Writes a secret/symmetric key to a JWK dictionary.
 void WriteSecretKey(const std::vector<uint8>& raw_key,
                     base::DictionaryValue* jwk_dict) {
   DCHECK(jwk_dict);
   jwk_dict->SetString("kty", "oct");
   // For a secret/symmetric key, the only extra JWK field is 'k', containing the
   // base64url encoding of the raw key.
   const base::StringPiece key_str(
       reinterpret_cast<const char*>(Uint8VectorStart(raw_key)), raw_key.size());
   jwk_dict->SetString("k", Base64EncodeUrlSafe(key_str));
@@ skipping 357 matching lines @@
 
   std::string json;
   base::JSONWriter::Write(&jwk_dict, &json);
   buffer->assign(json.data(), json.data() + json.size());
   return Status::Success();
 }
 
 }  // namespace webcrypto
 
 }  // namespace content