Refactor: Extract some duplicated code for verifying usages during import of asymmetric key.

content/child/webcrypto/webcrypto_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 CONTENT_CHILD_WEBCRYPTO_WEBCRYPTO_UTIL_H_
 #define CONTENT_CHILD_WEBCRYPTO_WEBCRYPTO_UTIL_H_
 
 #include <stdint.h>
 #include <string>
 
@@ skipping 63 matching lines @@
 // On success it is guaranteed that:
 //   * public_exponent is either 3 or 65537
 //   * modulus_length_bits is a multiple of 8
 //   * modulus_length is >= 256
 //   * modulus_length is <= 16K
 Status GetRsaKeyGenParameters(
     const blink::WebCryptoRsaHashedKeyGenParams* params,
     unsigned int* public_exponent,
     unsigned int* modulus_length_bits);
 
+// Verifies that |usages| is valid when importing a key of the given format.
+Status VerifyUsagesBeforeImportAsymmetricKey(
+    blink::WebCryptoKeyFormat format,
+    blink::WebCryptoKeyUsageMask all_public_key_usages,
+    blink::WebCryptoKeyUsageMask all_private_key_usages,
+    blink::WebCryptoKeyUsageMask usages);
+
 }  // namespace webcrypto
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_WEBCRYPTO_WEBCRYPTO_UTIL_H_