Fix error handling in POSIX version of the base::File::GetLength.

chrome/browser/media/webrtc/webrtc_browsertest_audio.cc

 // Copyright 2014 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 "chrome/browser/media/webrtc/webrtc_browsertest_audio.h"
 
 #include <stddef.h>
 
 #include "base/files/file.h"
 #include "base/files/file_path.h"
 #include "media/audio/audio_power_monitor.h"
 #include "media/audio/sounds/wav_audio_handler.h"
 #include "media/base/audio_bus.h"
 #include "media/base/audio_parameters.h"
 
 namespace {
 // Opens |wav_filename|, reads it and loads it as a wav file. This function will
 // bluntly trigger CHECKs if we can't read the file or if it's malformed. The
 // caller takes ownership of the returned data. The size of the data is stored
 // in |read_length|.
 std::unique_ptr<char[]> ReadWavFile(const base::FilePath& wav_filename,
                                     size_t* file_length) {
   base::File wav_file(
       wav_filename, base::File::FLAG_OPEN | base::File::FLAG_READ);
   if (!wav_file.IsValid()) {
     CHECK(false) << "Failed to read " << wav_filename.value();
     return nullptr;
   }
 
-  size_t wav_file_length = wav_file.GetLength();
+  int64_t wav_file_length64 = wav_file.GetLength();
+  if (wav_file_length64 < 0) {
+    PLOG(ERROR) << "GetLength " << wav_file.GetPlatformFile();
+    return nullptr;
+  }
+  if (wav_file_length64 > std::numeric_limits<int>::max()) {
+    LOG(ERROR) << "File is too big: " << wav_filename.value();
+    return nullptr;
+  }
+  int wav_file_length = static_cast<int>(wav_file_length64);
+  if (!wav_file_length) {
+    LOG(ERROR) << "Input file is empty: " << wav_filename.value();
+    return nullptr;
+  }
 
   std::unique_ptr<char[]> data(new char[wav_file_length]);
-  size_t read_bytes = wav_file.Read(0, data.get(), wav_file_length);
+  int read_bytes = wav_file.Read(0, data.get(), wav_file_length);
   if (read_bytes != wav_file_length) {
     LOG(ERROR) << "Failed to read all bytes of " << wav_filename.value();
     return nullptr;
   }
   *file_length = wav_file_length;
   return data;
 }
 }  // namespace
 
 namespace test {
@@ skipping 26 matching lines @@
       media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
       media::GuessChannelLayout(wav_audio_handler->num_channels()),
       wav_audio_handler->sample_rate(), wav_audio_handler->bits_per_sample(),
       wav_audio_handler->total_frames());
   file_parameters->set_channels_for_discrete(wav_audio_handler->num_channels());
 
   return power_monitor.ReadCurrentPowerAndClip().first;
 }
 
 }  // namespace test