[webcryto] Validate key usages during key creation.

content/child/webcrypto/webcrypto_util.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 "content/child/webcrypto/webcrypto_util.h"
 
 #include "base/base64.h"
 #include "base/logging.h"
 #include "base/strings/stringprintf.h"
 #include "content/child/webcrypto/status.h"
@@ skipping 161 matching lines @@
     case blink::WebCryptoAlgorithmIdAesCtr:
     case blink::WebCryptoAlgorithmIdAesGcm:
       *key_algorithm = blink::WebCryptoKeyAlgorithm::createAes(
           algorithm.id(), keylen_bytes * 8);
       return true;
     default:
       return false;
   }
 }
 
+bool ContainsKeyUsages(blink::WebCryptoKeyUsageMask a,
+                       blink::WebCryptoKeyUsageMask b) {
+  return (a & b) == b;
+}
+
 bool IsAlgorithmRsa(blink::WebCryptoAlgorithmId alg_id) {
   return alg_id == blink::WebCryptoAlgorithmIdRsaOaep ||
          alg_id == blink::WebCryptoAlgorithmIdRsaSsaPkcs1v1_5;
 }
 
+bool IsAlgorithmAsymmetric(blink::WebCryptoAlgorithmId alg_id) {
+  // TODO(padolph): include all other asymmetric algorithms once they are
+  // defined, e.g. EC and DH.
+  return IsAlgorithmRsa(alg_id);
+}
+
 }  // namespace webcrypto
 
 }  // namespace content