Add fuzzers for import of WebCrypto DER-encoded keys.

components/webcrypto/ec_import_key_pkcs8_fuzzer.cc

 // Copyright 2016 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 <stddef.h>
 #include <stdint.h>
-#include <vector>
 
-#include "media/cdm/cenc_utils.h"
+#include "components/webcrypto/fuzzer_support.h"
 
 // Entry point for LibFuzzer.
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
-  std::vector<uint8_t> input(data, data + size);
-  media::ValidatePsshInput(input);
+  webcrypto::ImportEcKeyFromDerFuzzData(data, size,
+                                        blink::WebCryptoKeyFormatPkcs8);
   return 0;
 }