message: Reference WebCryptoNamedCurve instead of using hard-coded string.
diff: const EccCryptoContext = require('../../../../../core/src/main/javascript/crypto/EccCryptoContext.js');
  const WebCryptoAlgorithm = require('../../../../../core/src/main/javascript/crypto/WebCryptoAlgorithm.js');
  const WebCryptoUsage = require('../../../../../core/src/main/javascript/crypto/WebCryptoUsage.js');
  + const WebCryptoNamedCurve = require('../../../../../core/src/main/javascript/crypto/WebCryptoNamedCurve.js');
  const KeyFormat = require('../../../../../core/src/main/javascript/crypto/KeyFormat.js');
  const MslInternalException = require('../../../../../core/src/main/javascript/MslInternalException.js');
  const Base64 = require('../../../../../core/src/main/javascript/util/Base64.js');
  (function() {
  var _algo = WebCryptoAlgorithm.ECDSA_SHA256;
  - _algo['namedCurve'] = 'P-256';
  + _algo['namedCurve'] = WebCryptoNamedCurve.P_256;
  var pubKeyEncoded = Base64.decode(ECC_PUBKEY_B64);
  var privKeyEncoded = Base64.decode(ECC_PRIVKEY_B64);
  