Refactor WebCrypto code

content/child/webcrypto/webcrypto_util.cc

Index: content/child/webcrypto/webcrypto_util.cc
diff --git a/content/child/webcrypto/webcrypto_util.cc b/content/child/webcrypto/webcrypto_util.cc
index 87ac17465e8639fa40b879cbdaa3d5caa91cbb30..45eaa8de2d080c6bfbca61ff3d888c3410b21f66 100644
--- a/content/child/webcrypto/webcrypto_util.cc
+++ b/content/child/webcrypto/webcrypto_util.cc
@@ -191,6 +191,12 @@ bool ContainsKeyUsages(blink::WebCryptoKeyUsageMask a,
   return (a & b) == b;
 }
 
+// TODO(eroman): Move this helper to WebCryptoKey.
+bool KeyUsageAllows(const blink::WebCryptoKey& key,
+                    const blink::WebCryptoKeyUsage usage) {
+  return ((key.usages() & usage) != 0);
+}
+
 bool IsAlgorithmRsa(blink::WebCryptoAlgorithmId alg_id) {
   return alg_id == blink::WebCryptoAlgorithmIdRsaOaep ||
          alg_id == blink::WebCryptoAlgorithmIdRsaSsaPkcs1v1_5;