Add media/audio/wav_audio_handler_fuzzer

This adds fuzzer coverage for wav_audio_handler.cc.

Fuzzer coverage report: https://chromium-coverage.appspot.com/reports/737219_fuzzers_only/linux/chromium/src/media/audio/wav_audio_handler.cc.html

Change-Id: I60176aba90301bcab648029511a27c16c93ef736
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2033443Reviewed-by: Olga Sharonova <olka@chromium.org>
Commit-Queue: Dan McArdle <dmcardle@chromium.org>
Cr-Commit-Position: refs/heads/master@{#737778}

media/audio/BUILD.gn

@@ -4,6 +4,7 @@
 
 import("//build/config/linux/pkg_config.gni")
 import("//media/media_options.gni")
+import("//testing/libfuzzer/fuzzer_test.gni")
 import("//tools/generate_stubs/rules.gni")
 
 # When libpulse is not directly linked, use stubs to allow for dlopening of the
@@ -38,6 +39,7 @@ source_set("audio") {
   # is a roll-up target which is part of the //media component. Most other DEPs
   # should be using //media and not directly DEP this roll-up target.
   visibility = [
+    ":wav_audio_handler_fuzzer",
     "//media",
 
     "//media/renderers",
@@ -451,3 +453,12 @@ source_set("unit_tests") {
     ]
   }
 }
+
+fuzzer_test("wav_audio_handler_fuzzer") {
+  sources = [ "wav_audio_handler_fuzzer.cc" ]
+  deps = [
+    ":audio",
+    "//base",
+    "//media:test_support",
+  ]
+}

media/audio/wav_audio_handler_fuzzer.cc

+// Copyright 2020 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 <memory>
+
+#include "base/logging.h"
+#include "media/audio/wav_audio_handler.h"
+#include "media/base/audio_bus.h"
+
+struct Environment {
+  Environment() { logging::SetMinLogLevel(logging::LOG_FATAL); }
+};
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  static Environment env;
+  base::StringPiece wav_data(reinterpret_cast<const char*>(data), size);
+  std::unique_ptr<media::WavAudioHandler> handler =
+      media::WavAudioHandler::Create(wav_data);
+  if (!handler) {
+    return 0;
+  }
+
+  std::unique_ptr<media::AudioBus> audio_bus =
+      media::AudioBus::Create(handler->num_channels(), handler->total_frames());
+  size_t bytes_written;
+  handler->CopyTo(audio_bus.get(), 0, &bytes_written);
+  return 0;
+}