[libfuzzer] Add fuzzer for third_party/hunspell with dictionary.

Ported from google3 with minor changes.

R=aizatsky@chromium.org, kcc@chromium.org, ochang@chromium.org, rouslan@chromium.org, phajdan.jr@chromium.org

BUG=539572

Review-Url: https://codereview.chromium.org/2012443002
Cr-Commit-Position: refs/heads/master@{#398274}

third_party/hunspell/BUILD.gn

@@ -2,6 +2,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//testing/libfuzzer/fuzzer_test.gni")
+
 config("hunspell_config") {
   defines = [
     "HUNSPELL_STATIC",
@@ -109,3 +111,16 @@ source_set("hunspell") {
     ]
   }
 }
+
+fuzzer_test("hunspell_fuzzer") {
+  sources = [
+    "fuzz/hunspell_fuzzer.cc",
+    "fuzz/hunspell_fuzzer_dictionary.h",
+  ]
+  deps = [
+    ":hunspell",
+  ]
+
+  # This is a dictionary for the fuzzer, not a spellcheck dictionary.
+  dict = "fuzz/hunspell.dict"
+}

third_party/hunspell/fuzz/hunspell_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 "third_party/hunspell/src/hunspell/hunspell.hxx"
+#include "third_party/hunspell/fuzz/hunspell_fuzzer_dictionary.h"
+
+// Entry point for LibFuzzer.
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  if (!size)
+    return 0;
+  
+  static Hunspell* hunspell = new Hunspell(
+      reinterpret_cast<const unsigned char*>(kHunspellDictionary),
+      sizeof(kHunspellDictionary));
+
+  std::string data_string(reinterpret_cast<const char*>(data), size);
+  hunspell->spell(data_string.c_str());
+
+  char** suggestions = nullptr;
+  int suggetion_length = hunspell->suggest(&suggestions, data_string.c_str());
+  hunspell->free_list(&suggestions, suggetion_length);
+
+  return 0;
+}

tools/checklicenses/checklicenses.py

@@ -83,6 +83,7 @@ WHITELISTED_LICENSES = [
     'MPL (v1.1) BSD (3 clause) LGPL (v2.1 or later)',
     'MPL (v1.1) BSD-like GPL (unversioned/unknown version)',
     'MPL (v1.1) BSD-like GPL (v2) LGPL (v2.1 or later)',
+    'MPL (v1.1) BSD-like LGPL (v2.1 or later)',
     'MPL (v1.1) BSD-like',
     'MPL (v1.1) GPL (unversioned/unknown version)',
     'MPL (v1.1) GPL (v2) LGPL (v2 or later)',