Initialize ICU before fuzzing the template URL parser.

testing/libfuzzer/fuzzers/template_url_parser_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 <random>
 #include <string>
 
+#include "base/at_exit.h"
+#include "base/i18n/icu_util.h"
 #include "components/search_engines/search_terms_data.h"
 #include "components/search_engines/template_url.h"
 #include "components/search_engines/template_url_parser.h"
 
 class PseudoRandomFilter : public TemplateURLParser::ParameterFilter {
  public:
   PseudoRandomFilter(uint32_t seed) : generator_(seed), pool_(0, 1) {}
   ~PseudoRandomFilter() override = default;
 
   bool KeepParameter(const std::string&, const std::string&) override {
     return pool_(generator_);
   }
 
  private:
   std::mt19937 generator_;
   std::uniform_int_distribution<uint8_t> pool_;
 };
 
 struct FuzzerFixedParams {
   uint32_t seed_;
 };
 
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   if (size < sizeof(FuzzerFixedParams)) {
     return 0;
   }
+  base::AtExitManager at_exit_manager;  // used by ICU integration.
+  base::i18n::InitializeICU();

[jochen (gone - plz use gerrit), 2017/04/18 07:08:57]

for posterity, we can't initialize ICU once per fuzzer run, instead, we should
add a function extern "C" int LLVMFuzzerInitialize(int* argc, char*** argv) that
initializes ICU

   const FuzzerFixedParams* params =
       reinterpret_cast<const FuzzerFixedParams*>(data);
   size -= sizeof(FuzzerFixedParams);
   const char* char_data = reinterpret_cast<const char*>(params + 1);
   PseudoRandomFilter filter(params->seed_);
   TemplateURLParser::Parse(SearchTermsData(), char_data, size, &filter);
   return 0;
 }