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 "components/webcrypto/fuzzer_support.h"
+#include <string>
+
+#include "net/dns/dns_hosts.h"
 
 // Entry point for LibFuzzer.
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
-  webcrypto::ImportRsaKeyFromDerFuzzData(data, size,
-                                         blink::WebCryptoKeyFormatPkcs8);
+  std::string input(reinterpret_cast<const char*>(data), size);
+  net::DnsHosts dns_hosts;
+  net::ParseHosts(input, &dns_hosts);

[mmenke, 2016/04/28 16:20:03]

I'd suggest calling ParseHostsWithCommaModeForTesting with both comma modes on
the input, instead of ParseHosts, just to make sure we cover all our bases.

[Zhongyi Shi, 2016/04/28 17:35:17]

Done. Thanks:D

   return 0;
 }