Add a fuzzer for DNS hosts parser

net/dns/dns_hosts_parse_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 <string>
+
+#include "net/dns/dns_hosts.h"
+
+// Entry point for LibFuzzer.
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  std::string input(reinterpret_cast<const char*>(data), size);
+  net::DnsHosts dns_hosts;
+  net::ParseHostsWithCommaModeForTesting(input, &dns_hosts,
+                                         net::PARSE_HOSTS_COMMA_IS_TOKEN);
+  dns_hosts.clear();
+  net::ParseHostsWithCommaModeForTesting(input, &dns_hosts,
+                                         net::PARSE_HOSTS_COMMA_IS_WHITESPACE);
+  return 0;
+}