Add simple fuzzer for HttpAuthChallengeTokenizer

net/http/http_auth_challenge_tokenizer_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 <string>
+
+#include "net/http/http_auth_challenge_tokenizer.h"
+#include "net/http/http_util.h"
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  std::string input(reinterpret_cast<const char*>(data), size);
+  net::HttpAuthChallengeTokenizer tokenizer(input.begin(), input.end());
+  net::HttpUtil::NameValuePairsIterator parameters = tokenizer.param_pairs();
+  while (parameters.GetNext()) {
+  }
+  tokenizer.base64_param();
+  return 0;
+}