Add POLQA to low bandwidth audio test

webrtc/audio/test/low_bandwidth_audio_test.cc

Index: webrtc/audio/test/low_bandwidth_audio_test.cc
diff --git a/webrtc/audio/test/low_bandwidth_audio_test.cc b/webrtc/audio/test/low_bandwidth_audio_test.cc
index 65f28fa6a3385ccc2c30dbbac9ad332910202f54..c5dc6d3628a5571159bfd168b99ee8315650716e 100644
--- a/webrtc/audio/test/low_bandwidth_audio_test.cc
+++ b/webrtc/audio/test/low_bandwidth_audio_test.cc
@@ -10,6 +10,7 @@
 
 #include <algorithm>
 
+#include "gflags/gflags.h"
 #include "webrtc/audio/test/low_bandwidth_audio_test.h"
 #include "webrtc/common_audio/wav_file.h"
 #include "webrtc/test/gtest.h"
@@ -20,8 +21,8 @@ namespace {
 // Wait half a second between stopping sending and stopping receiving audio.
 constexpr int kExtraRecordTimeMs = 500;
 
-// The best that can be done with PESQ.
-constexpr int kAudioFileBitRate = 16000;
+DEFINE_int32(sampling_frequency, 16000,

[kwiberg-webrtc, 2017/04/12 07:13:49]

As always, I'm going to suggest that you call this sample_rate_hz. But you
decide.

[oprypin_webrtc, 2017/04/12 11:24:56]

Done.

+             "Sampling frequency (Hz) of the produced audio files.");

[kwiberg-webrtc, 2017/04/12 07:13:49]

Look it up before you take my advice because I'm not too familiar with gflags,
but I think you may be supposed to put them in the global namespace.

[oprypin_webrtc, 2017/04/12 11:24:56]

OK. Indeed, flags are usually put in the global namespace.

 }  // namespace
 
 namespace webrtc {
@@ -41,14 +42,16 @@ size_t AudioQualityTest::GetNumFlexfecStreams() const {
 }
 
 std::string AudioQualityTest::AudioInputFile() {
-  return test::ResourcePath("voice_engine/audio_tiny16", "wav");
+  return test::ResourcePath("voice_engine/audio_tiny" +
+                            std::to_string(FLAGS_sampling_frequency / 1000),
+                            "wav");
 }
 
 std::string AudioQualityTest::AudioOutputFile() {
   const ::testing::TestInfo* const test_info =
       ::testing::UnitTest::GetInstance()->current_test_info();
-  return webrtc::test::OutputPath() +
-      "LowBandwidth_" + test_info->name() + ".wav";
+  return webrtc::test::OutputPath() + "LowBandwidth_" + test_info->name() +
+      "_" + std::to_string(FLAGS_sampling_frequency / 1000) + ".wav";

[kwiberg-webrtc, 2017/04/12 07:13:49]

You construct this name more than once. Utility function?

[oprypin_webrtc, 2017/04/12 11:24:56]

Done.

 }
 
 std::unique_ptr<test::FakeAudioDevice::Capturer>
@@ -59,7 +62,7 @@ std::unique_ptr<test::FakeAudioDevice::Capturer>
 std::unique_ptr<test::FakeAudioDevice::Renderer>
     AudioQualityTest::CreateRenderer() {
   return test::FakeAudioDevice::CreateBoundedWavFileWriter(
-      AudioOutputFile(), kAudioFileBitRate);
+      AudioOutputFile(), FLAGS_sampling_frequency);
 }
 
 void AudioQualityTest::OnFakeAudioDevicesCreated(