Migrate WebRTC test infra to ABSL_FLAG.

This is the last CL required to migrate WebRTC to ABSL_FLAG, rtc::Flag
will be removed soon after this one lands.

Bug: webrtc:10616
Change-Id: I2807cec39e28a2737d2c49e2dc23f2a6f98d08f0
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/145727
Reviewed-by: Tommi <tommi@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28606}
diff --git a/modules/audio_coding/neteq/neteq_unittest.cc b/modules/audio_coding/neteq/neteq_unittest.cc
index 9f7d04d..7835096 100644
--- a/modules/audio_coding/neteq/neteq_unittest.cc
+++ b/modules/audio_coding/neteq/neteq_unittest.cc
@@ -20,6 +20,7 @@
 #include <string>
 #include <vector>
 
+#include "absl/flags/flag.h"
 #include "api/audio/audio_frame.h"
 #include "api/audio_codecs/builtin_audio_decoder_factory.h"
 #include "modules/audio_coding/codecs/pcm16b/pcm16b.h"
@@ -40,9 +41,6 @@
 #include "test/gtest.h"
 #include "test/testsupport/file_utils.h"
 
-// This must come after test/gtest.h
-#include "rtc_base/flags.h"  // NOLINT(build/include)
-
 #ifdef WEBRTC_NETEQ_UNITTEST_BITEXACT
 RTC_PUSH_IGNORING_WUNDEF()
 #ifdef WEBRTC_ANDROID_PLATFORM_BUILD
@@ -53,7 +51,7 @@
 RTC_POP_IGNORING_WUNDEF()
 #endif
 
-WEBRTC_DEFINE_bool(gen_ref, false, "Generate reference files.");
+ABSL_FLAG(bool, gen_ref, false, "Generate reference files.");
 
 namespace webrtc {
 
@@ -470,7 +468,7 @@
                        "3689c9f0ab9e50cefab3e44c37c3d7aa0de82ca4");
 
   DecodeAndCompare(input_rtp_file, output_checksum, network_stats_checksum,
-                   FLAG_gen_ref);
+                   absl::GetFlag(FLAGS_gen_ref));
 }
 
 #if !defined(WEBRTC_IOS) && defined(WEBRTC_NETEQ_UNITTEST_BITEXACT) && \
@@ -499,7 +497,7 @@
                        "0b3d34baffaf651812ffaf06ea1b5ce45ea1c47a");
 
   DecodeAndCompare(input_rtp_file, output_checksum, network_stats_checksum,
-                   FLAG_gen_ref);
+                   absl::GetFlag(FLAGS_gen_ref));
 }
 
 #if !defined(WEBRTC_IOS) && defined(WEBRTC_NETEQ_UNITTEST_BITEXACT) && \
@@ -523,7 +521,7 @@
       "bab58dc587d956f326056d7340c96eb9d2d3cc21";
 
   DecodeAndCompare(input_rtp_file, output_checksum, network_stats_checksum,
-                   FLAG_gen_ref);
+                   absl::GetFlag(FLAGS_gen_ref));
 }
 
 // Use fax mode to avoid time-scaling. This is to simplify the testing of
diff --git a/modules/audio_coding/neteq/test/neteq_ilbc_quality_test.cc b/modules/audio_coding/neteq/test/neteq_ilbc_quality_test.cc
index 5d2df77..1004141 100644
--- a/modules/audio_coding/neteq/test/neteq_ilbc_quality_test.cc
+++ b/modules/audio_coding/neteq/test/neteq_ilbc_quality_test.cc
@@ -10,13 +10,15 @@
 
 #include <memory>
 
+#include "absl/flags/flag.h"
 #include "modules/audio_coding/codecs/ilbc/audio_encoder_ilbc.h"
 #include "modules/audio_coding/neteq/tools/neteq_quality_test.h"
 #include "rtc_base/checks.h"
-#include "rtc_base/flags.h"
 #include "rtc_base/numerics/safe_conversions.h"
 #include "test/testsupport/file_utils.h"
 
+ABSL_FLAG(int, frame_size_ms, 20, "Codec frame size (milliseconds).");
+
 using ::testing::InitGoogleTest;
 
 namespace webrtc {
@@ -24,28 +26,27 @@
 namespace {
 static const int kInputSampleRateKhz = 8;
 static const int kOutputSampleRateKhz = 8;
-
-WEBRTC_DEFINE_int(frame_size_ms, 20, "Codec frame size (milliseconds).");
-
 }  // namespace
 
 class NetEqIlbcQualityTest : public NetEqQualityTest {
  protected:
   NetEqIlbcQualityTest()
-      : NetEqQualityTest(FLAG_frame_size_ms,
+      : NetEqQualityTest(absl::GetFlag(FLAGS_frame_size_ms),
                          kInputSampleRateKhz,
                          kOutputSampleRateKhz,
                          SdpAudioFormat("ilbc", 8000, 1)) {
     // Flag validation
-    RTC_CHECK(FLAG_frame_size_ms == 20 || FLAG_frame_size_ms == 30 ||
-              FLAG_frame_size_ms == 40 || FLAG_frame_size_ms == 60)
+    RTC_CHECK(absl::GetFlag(FLAGS_frame_size_ms) == 20 ||
+              absl::GetFlag(FLAGS_frame_size_ms) == 30 ||
+              absl::GetFlag(FLAGS_frame_size_ms) == 40 ||
+              absl::GetFlag(FLAGS_frame_size_ms) == 60)
         << "Invalid frame size, should be 20, 30, 40, or 60 ms.";
   }
 
   void SetUp() override {
     ASSERT_EQ(1u, channels_) << "iLBC supports only mono audio.";
     AudioEncoderIlbcConfig config;
-    config.frame_size_ms = FLAG_frame_size_ms;
+    config.frame_size_ms = absl::GetFlag(FLAGS_frame_size_ms);
     encoder_.reset(new AudioEncoderIlbcImpl(config, 102));
     NetEqQualityTest::SetUp();
   }
diff --git a/modules/audio_coding/neteq/test/neteq_isac_quality_test.cc b/modules/audio_coding/neteq/test/neteq_isac_quality_test.cc
index 94a5a86..6a096c3 100644
--- a/modules/audio_coding/neteq/test/neteq_isac_quality_test.cc
+++ b/modules/audio_coding/neteq/test/neteq_isac_quality_test.cc
@@ -8,9 +8,11 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
+#include "absl/flags/flag.h"
 #include "modules/audio_coding/codecs/isac/fix/include/isacfix.h"
 #include "modules/audio_coding/neteq/tools/neteq_quality_test.h"
-#include "rtc_base/flags.h"
+
+ABSL_FLAG(int, bit_rate_kbps, 32, "Target bit rate (kbps).");
 
 using ::testing::InitGoogleTest;
 
@@ -20,9 +22,6 @@
 static const int kIsacBlockDurationMs = 30;
 static const int kIsacInputSamplingKhz = 16;
 static const int kIsacOutputSamplingKhz = 16;
-
-WEBRTC_DEFINE_int(bit_rate_kbps, 32, "Target bit rate (kbps).");
-
 }  // namespace
 
 class NetEqIsacQualityTest : public NetEqQualityTest {
@@ -46,9 +45,10 @@
                        kIsacOutputSamplingKhz,
                        SdpAudioFormat("isac", 16000, 1)),
       isac_encoder_(NULL),
-      bit_rate_kbps_(FLAG_bit_rate_kbps) {
+      bit_rate_kbps_(absl::GetFlag(FLAGS_bit_rate_kbps)) {
   // Flag validation
-  RTC_CHECK(FLAG_bit_rate_kbps >= 10 && FLAG_bit_rate_kbps <= 32)
+  RTC_CHECK(absl::GetFlag(FLAGS_bit_rate_kbps) >= 10 &&
+            absl::GetFlag(FLAGS_bit_rate_kbps) <= 32)
       << "Invalid bit rate, should be between 10 and 32 kbps.";
 }
 
diff --git a/modules/audio_coding/neteq/test/neteq_opus_quality_test.cc b/modules/audio_coding/neteq/test/neteq_opus_quality_test.cc
index 6a6b665..eb7c2c1 100644
--- a/modules/audio_coding/neteq/test/neteq_opus_quality_test.cc
+++ b/modules/audio_coding/neteq/test/neteq_opus_quality_test.cc
@@ -8,10 +8,30 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
+#include "absl/flags/flag.h"
 #include "modules/audio_coding/codecs/opus/opus_inst.h"
 #include "modules/audio_coding/codecs/opus/opus_interface.h"
 #include "modules/audio_coding/neteq/tools/neteq_quality_test.h"
-#include "rtc_base/flags.h"
+
+ABSL_FLAG(int, bit_rate_kbps, 32, "Target bit rate (kbps).");
+
+ABSL_FLAG(int,
+          complexity,
+          10,
+          "Complexity: 0 ~ 10 -- defined as in Opus"
+          "specification.");
+
+ABSL_FLAG(int, maxplaybackrate, 48000, "Maximum playback rate (Hz).");
+
+ABSL_FLAG(int, application, 0, "Application mode: 0 -- VOIP, 1 -- Audio.");
+
+ABSL_FLAG(int, reported_loss_rate, 10, "Reported percentile of packet loss.");
+
+ABSL_FLAG(bool, fec, false, "Enable FEC for encoding (-nofec to disable).");
+
+ABSL_FLAG(bool, dtx, false, "Enable DTX for encoding (-nodtx to disable).");
+
+ABSL_FLAG(int, sub_packets, 1, "Number of sub packets to repacketize.");
 
 using ::testing::InitGoogleTest;
 
@@ -21,28 +41,6 @@
 
 static const int kOpusBlockDurationMs = 20;
 static const int kOpusSamplingKhz = 48;
-
-WEBRTC_DEFINE_int(bit_rate_kbps, 32, "Target bit rate (kbps).");
-
-WEBRTC_DEFINE_int(complexity,
-                  10,
-                  "Complexity: 0 ~ 10 -- defined as in Opus"
-                  "specification.");
-
-WEBRTC_DEFINE_int(maxplaybackrate, 48000, "Maximum playback rate (Hz).");
-
-WEBRTC_DEFINE_int(application, 0, "Application mode: 0 -- VOIP, 1 -- Audio.");
-
-WEBRTC_DEFINE_int(reported_loss_rate,
-                  10,
-                  "Reported percentile of packet loss.");
-
-WEBRTC_DEFINE_bool(fec, false, "Enable FEC for encoding (-nofec to disable).");
-
-WEBRTC_DEFINE_bool(dtx, false, "Enable DTX for encoding (-nodtx to disable).");
-
-WEBRTC_DEFINE_int(sub_packets, 1, "Number of sub packets to repacketize.");
-
 }  // namespace
 
 class NetEqOpusQualityTest : public NetEqQualityTest {
@@ -70,7 +68,7 @@
 };
 
 NetEqOpusQualityTest::NetEqOpusQualityTest()
-    : NetEqQualityTest(kOpusBlockDurationMs * FLAG_sub_packets,
+    : NetEqQualityTest(kOpusBlockDurationMs * absl::GetFlag(FLAGS_sub_packets),
                        kOpusSamplingKhz,
                        kOpusSamplingKhz,
                        SdpAudioFormat("opus", 48000, 2)),
@@ -78,27 +76,32 @@
       repacketizer_(NULL),
       sub_block_size_samples_(
           static_cast<size_t>(kOpusBlockDurationMs * kOpusSamplingKhz)),
-      bit_rate_kbps_(FLAG_bit_rate_kbps),
-      fec_(FLAG_fec),
-      dtx_(FLAG_dtx),
-      complexity_(FLAG_complexity),
-      maxplaybackrate_(FLAG_maxplaybackrate),
-      target_loss_rate_(FLAG_reported_loss_rate),
-      sub_packets_(FLAG_sub_packets) {
+      bit_rate_kbps_(absl::GetFlag(FLAGS_bit_rate_kbps)),
+      fec_(absl::GetFlag(FLAGS_fec)),
+      dtx_(absl::GetFlag(FLAGS_dtx)),
+      complexity_(absl::GetFlag(FLAGS_complexity)),
+      maxplaybackrate_(absl::GetFlag(FLAGS_maxplaybackrate)),
+      target_loss_rate_(absl::GetFlag(FLAGS_reported_loss_rate)),
+      sub_packets_(absl::GetFlag(FLAGS_sub_packets)) {
   // Flag validation
-  RTC_CHECK(FLAG_bit_rate_kbps >= 6 && FLAG_bit_rate_kbps <= 510)
+  RTC_CHECK(absl::GetFlag(FLAGS_bit_rate_kbps) >= 6 &&
+            absl::GetFlag(FLAGS_bit_rate_kbps) <= 510)
       << "Invalid bit rate, should be between 6 and 510 kbps.";
 
-  RTC_CHECK(FLAG_complexity >= -1 && FLAG_complexity <= 10)
+  RTC_CHECK(absl::GetFlag(FLAGS_complexity) >= -1 &&
+            absl::GetFlag(FLAGS_complexity) <= 10)
       << "Invalid complexity setting, should be between 0 and 10.";
 
-  RTC_CHECK(FLAG_application == 0 || FLAG_application == 1)
+  RTC_CHECK(absl::GetFlag(FLAGS_application) == 0 ||
+            absl::GetFlag(FLAGS_application) == 1)
       << "Invalid application mode, should be 0 or 1.";
 
-  RTC_CHECK(FLAG_reported_loss_rate >= 0 && FLAG_reported_loss_rate <= 100)
+  RTC_CHECK(absl::GetFlag(FLAGS_reported_loss_rate) >= 0 &&
+            absl::GetFlag(FLAGS_reported_loss_rate) <= 100)
       << "Invalid packet loss percentile, should be between 0 and 100.";
 
-  RTC_CHECK(FLAG_sub_packets >= 1 && FLAG_sub_packets <= 3)
+  RTC_CHECK(absl::GetFlag(FLAGS_sub_packets) >= 1 &&
+            absl::GetFlag(FLAGS_sub_packets) <= 3)
       << "Invalid number of sub packets, should be between 1 and 3.";
 
   // Redefine decoder type if input is stereo.
@@ -106,7 +109,7 @@
     audio_format_ = SdpAudioFormat(
         "opus", 48000, 2, std::map<std::string, std::string>{{"stereo", "1"}});
   }
-  application_ = FLAG_application;
+  application_ = absl::GetFlag(FLAGS_application);
 }
 
 void NetEqOpusQualityTest::SetUp() {
diff --git a/modules/audio_coding/neteq/test/neteq_pcm16b_quality_test.cc b/modules/audio_coding/neteq/test/neteq_pcm16b_quality_test.cc
index 9ec9d44..c3e160c 100644
--- a/modules/audio_coding/neteq/test/neteq_pcm16b_quality_test.cc
+++ b/modules/audio_coding/neteq/test/neteq_pcm16b_quality_test.cc
@@ -10,13 +10,15 @@
 
 #include <memory>
 
+#include "absl/flags/flag.h"
 #include "modules/audio_coding/codecs/pcm16b/audio_encoder_pcm16b.h"
 #include "modules/audio_coding/neteq/tools/neteq_quality_test.h"
 #include "rtc_base/checks.h"
-#include "rtc_base/flags.h"
 #include "rtc_base/numerics/safe_conversions.h"
 #include "test/testsupport/file_utils.h"
 
+ABSL_FLAG(int, frame_size_ms, 20, "Codec frame size (milliseconds).");
+
 using ::testing::InitGoogleTest;
 
 namespace webrtc {
@@ -24,27 +26,25 @@
 namespace {
 static const int kInputSampleRateKhz = 48;
 static const int kOutputSampleRateKhz = 48;
-
-WEBRTC_DEFINE_int(frame_size_ms, 20, "Codec frame size (milliseconds).");
-
 }  // namespace
 
 class NetEqPcm16bQualityTest : public NetEqQualityTest {
  protected:
   NetEqPcm16bQualityTest()
-      : NetEqQualityTest(FLAG_frame_size_ms,
+      : NetEqQualityTest(absl::GetFlag(FLAGS_frame_size_ms),
                          kInputSampleRateKhz,
                          kOutputSampleRateKhz,
                          SdpAudioFormat("l16", 48000, 1)) {
     // Flag validation
-    RTC_CHECK(FLAG_frame_size_ms >= 10 && FLAG_frame_size_ms <= 60 &&
-              (FLAG_frame_size_ms % 10) == 0)
+    RTC_CHECK(absl::GetFlag(FLAGS_frame_size_ms) >= 10 &&
+              absl::GetFlag(FLAGS_frame_size_ms) <= 60 &&
+              (absl::GetFlag(FLAGS_frame_size_ms) % 10) == 0)
         << "Invalid frame size, should be 10, 20, ..., 60 ms.";
   }
 
   void SetUp() override {
     AudioEncoderPcm16B::Config config;
-    config.frame_size_ms = FLAG_frame_size_ms;
+    config.frame_size_ms = absl::GetFlag(FLAGS_frame_size_ms);
     config.sample_rate_hz = 48000;
     config.num_channels = channels_;
     encoder_.reset(new AudioEncoderPcm16B(config));
diff --git a/modules/audio_coding/neteq/test/neteq_pcmu_quality_test.cc b/modules/audio_coding/neteq/test/neteq_pcmu_quality_test.cc
index 62a184e..d22170c 100644
--- a/modules/audio_coding/neteq/test/neteq_pcmu_quality_test.cc
+++ b/modules/audio_coding/neteq/test/neteq_pcmu_quality_test.cc
@@ -10,13 +10,15 @@
 
 #include <memory>
 
+#include "absl/flags/flag.h"
 #include "modules/audio_coding/codecs/g711/audio_encoder_pcm.h"
 #include "modules/audio_coding/neteq/tools/neteq_quality_test.h"
 #include "rtc_base/checks.h"
-#include "rtc_base/flags.h"
 #include "rtc_base/numerics/safe_conversions.h"
 #include "test/testsupport/file_utils.h"
 
+ABSL_FLAG(int, frame_size_ms, 20, "Codec frame size (milliseconds).");
+
 using ::testing::InitGoogleTest;
 
 namespace webrtc {
@@ -24,28 +26,26 @@
 namespace {
 static const int kInputSampleRateKhz = 8;
 static const int kOutputSampleRateKhz = 8;
-
-WEBRTC_DEFINE_int(frame_size_ms, 20, "Codec frame size (milliseconds).");
-
 }  // namespace
 
 class NetEqPcmuQualityTest : public NetEqQualityTest {
  protected:
   NetEqPcmuQualityTest()
-      : NetEqQualityTest(FLAG_frame_size_ms,
+      : NetEqQualityTest(absl::GetFlag(FLAGS_frame_size_ms),
                          kInputSampleRateKhz,
                          kOutputSampleRateKhz,
                          SdpAudioFormat("pcmu", 8000, 1)) {
     // Flag validation
-    RTC_CHECK(FLAG_frame_size_ms >= 10 && FLAG_frame_size_ms <= 60 &&
-              (FLAG_frame_size_ms % 10) == 0)
+    RTC_CHECK(absl::GetFlag(FLAGS_frame_size_ms) >= 10 &&
+              absl::GetFlag(FLAGS_frame_size_ms) <= 60 &&
+              (absl::GetFlag(FLAGS_frame_size_ms) % 10) == 0)
         << "Invalid frame size, should be 10, 20, ..., 60 ms.";
   }
 
   void SetUp() override {
     ASSERT_EQ(1u, channels_) << "PCMu supports only mono audio.";
     AudioEncoderPcmU::Config config;
-    config.frame_size_ms = FLAG_frame_size_ms;
+    config.frame_size_ms = absl::GetFlag(FLAGS_frame_size_ms);
     encoder_.reset(new AudioEncoderPcmU(config));
     NetEqQualityTest::SetUp();
   }
diff --git a/modules/audio_coding/neteq/test/neteq_speed_test.cc b/modules/audio_coding/neteq/test/neteq_speed_test.cc
index 70777a2..a72b200 100644
--- a/modules/audio_coding/neteq/test/neteq_speed_test.cc
+++ b/modules/audio_coding/neteq/test/neteq_speed_test.cc
@@ -11,18 +11,21 @@
 #include <stdio.h>
 
 #include <iostream>
+#include <vector>
 
+#include "absl/flags/flag.h"
+#include "absl/flags/parse.h"
 #include "modules/audio_coding/neteq/tools/neteq_performance_test.h"
-#include "rtc_base/flags.h"
+#include "rtc_base/checks.h"
 
 // Define command line flags.
-WEBRTC_DEFINE_int(runtime_ms, 10000, "Simulated runtime in ms.");
-WEBRTC_DEFINE_int(lossrate, 10, "Packet lossrate; drop every N packets.");
-WEBRTC_DEFINE_float(drift, 0.1f, "Clockdrift factor.");
-WEBRTC_DEFINE_bool(help, false, "Print this message.");
+ABSL_FLAG(int, runtime_ms, 10000, "Simulated runtime in ms.");
+ABSL_FLAG(int, lossrate, 10, "Packet lossrate; drop every N packets.");
+ABSL_FLAG(float, drift, 0.1f, "Clockdrift factor.");
 
 int main(int argc, char* argv[]) {
-  std::string program_name = argv[0];
+  std::vector<char*> args = absl::ParseCommandLine(argc, argv);
+  std::string program_name = args[0];
   std::string usage =
       "Tool for measuring the speed of NetEq.\n"
       "Usage: " +
@@ -32,21 +35,18 @@
       "  --lossrate=N           drop every N packets; default is 10\n"
       "  --drift=F              clockdrift factor between 0.0 and 1.0; "
       "default is 0.1\n";
-  if (rtc::FlagList::SetFlagsFromCommandLine(&argc, argv, true) || FLAG_help ||
-      argc != 1) {
+  if (args.size() != 1) {
     printf("%s", usage.c_str());
-    if (FLAG_help) {
-      rtc::FlagList::Print(nullptr, false);
-      return 0;
-    }
     return 1;
   }
-  RTC_CHECK_GT(FLAG_runtime_ms, 0);
-  RTC_CHECK_GE(FLAG_lossrate, 0);
-  RTC_CHECK(FLAG_drift >= 0.0 && FLAG_drift < 1.0);
+  RTC_CHECK_GT(absl::GetFlag(FLAGS_runtime_ms), 0);
+  RTC_CHECK_GE(absl::GetFlag(FLAGS_lossrate), 0);
+  RTC_CHECK(absl::GetFlag(FLAGS_drift) >= 0.0 &&
+            absl::GetFlag(FLAGS_drift) < 1.0);
 
   int64_t result = webrtc::test::NetEqPerformanceTest::Run(
-      FLAG_runtime_ms, FLAG_lossrate, FLAG_drift);
+      absl::GetFlag(FLAGS_runtime_ms), absl::GetFlag(FLAGS_lossrate),
+      absl::GetFlag(FLAGS_drift));
   if (result <= 0) {
     std::cout << "There was an error" << std::endl;
     return -1;
diff --git a/modules/audio_coding/neteq/tools/neteq_quality_test.cc b/modules/audio_coding/neteq/tools/neteq_quality_test.cc
index 01d2a2d..0adc21d 100644
--- a/modules/audio_coding/neteq/tools/neteq_quality_test.cc
+++ b/modules/audio_coding/neteq/tools/neteq_quality_test.cc
@@ -14,12 +14,75 @@
 
 #include <cmath>
 
+#include "absl/flags/flag.h"
+#include "modules/audio_coding/neteq/tools/neteq_quality_test.h"
 #include "modules/audio_coding/neteq/tools/output_audio_file.h"
 #include "modules/audio_coding/neteq/tools/output_wav_file.h"
 #include "modules/audio_coding/neteq/tools/resample_input_audio_file.h"
 #include "rtc_base/checks.h"
 #include "test/testsupport/file_utils.h"
 
+const std::string& DefaultInFilename() {
+  static const std::string path =
+      ::webrtc::test::ResourcePath("audio_coding/speech_mono_16kHz", "pcm");
+  return path;
+}
+
+const std::string& DefaultOutFilename() {
+  static const std::string path =
+      ::webrtc::test::OutputPath() + "neteq_quality_test_out.pcm";
+  return path;
+}
+
+ABSL_FLAG(
+    std::string,
+    in_filename,
+    DefaultInFilename(),
+    "Filename for input audio (specify sample rate with --input_sample_rate, "
+    "and channels with --channels).");
+
+ABSL_FLAG(int, input_sample_rate, 16000, "Sample rate of input file in Hz.");
+
+ABSL_FLAG(int, channels, 1, "Number of channels in input audio.");
+
+ABSL_FLAG(std::string,
+          out_filename,
+          DefaultOutFilename(),
+          "Name of output audio file.");
+
+ABSL_FLAG(
+    int,
+    runtime_ms,
+    10000,
+    "Simulated runtime (milliseconds). -1 will consume the complete file.");
+
+ABSL_FLAG(int, packet_loss_rate, 10, "Percentile of packet loss.");
+
+ABSL_FLAG(int,
+          random_loss_mode,
+          ::webrtc::test::kUniformLoss,
+          "Random loss mode: 0--no loss, 1--uniform loss, 2--Gilbert Elliot "
+          "loss, 3--fixed loss.");
+
+ABSL_FLAG(int,
+          burst_length,
+          30,
+          "Burst length in milliseconds, only valid for Gilbert Elliot loss.");
+
+ABSL_FLAG(float, drift_factor, 0.0, "Time drift factor.");
+
+ABSL_FLAG(int,
+          preload_packets,
+          1,
+          "Preload the buffer with this many packets.");
+
+ABSL_FLAG(std::string,
+          loss_events,
+          "",
+          "List of loss events time and duration separated by comma: "
+          "<first_event_time> <first_event_duration>, <second_event_time> "
+          "<second_event_duration>, ...");
+
 namespace webrtc {
 namespace test {
 
@@ -28,17 +91,6 @@
 const int kInitSeed = 0x12345678;
 const int kPacketLossTimeUnitMs = 10;
 
-const std::string& DefaultInFilename() {
-  static const std::string path =
-      ResourcePath("audio_coding/speech_mono_16kHz", "pcm");
-  return path;
-}
-
-const std::string& DefaultOutFilename() {
-  static const std::string path = OutputPath() + "neteq_quality_test_out.pcm";
-  return path;
-}
-
 // Common validator for file names.
 static bool ValidateFilename(const std::string& value, bool is_output) {
   if (!is_output) {
@@ -53,51 +105,6 @@
   return true;
 }
 
-WEBRTC_DEFINE_string(
-    in_filename,
-    DefaultInFilename().c_str(),
-    "Filename for input audio (specify sample rate with --input_sample_rate, "
-    "and channels with --channels).");
-
-WEBRTC_DEFINE_int(input_sample_rate, 16000, "Sample rate of input file in Hz.");
-
-WEBRTC_DEFINE_int(channels, 1, "Number of channels in input audio.");
-
-WEBRTC_DEFINE_string(out_filename,
-                     DefaultOutFilename().c_str(),
-                     "Name of output audio file.");
-
-WEBRTC_DEFINE_int(
-    runtime_ms,
-    10000,
-    "Simulated runtime (milliseconds). -1 will consume the complete file.");
-
-WEBRTC_DEFINE_int(packet_loss_rate, 10, "Percentile of packet loss.");
-
-WEBRTC_DEFINE_int(
-    random_loss_mode,
-    kUniformLoss,
-    "Random loss mode: 0--no loss, 1--uniform loss, 2--Gilbert Elliot "
-    "loss, 3--fixed loss.");
-
-WEBRTC_DEFINE_int(
-    burst_length,
-    30,
-    "Burst length in milliseconds, only valid for Gilbert Elliot loss.");
-
-WEBRTC_DEFINE_float(drift_factor, 0.0, "Time drift factor.");
-
-WEBRTC_DEFINE_int(preload_packets,
-                  1,
-                  "Preload the buffer with this many packets.");
-
-WEBRTC_DEFINE_string(
-    loss_events,
-    "",
-    "List of loss events time and duration separated by comma: "
-    "<first_event_time> <first_event_duration>, <second_event_time> "
-    "<second_event_duration>, ...");
-
 // ProbTrans00Solver() is to calculate the transition probability from no-loss
 // state to itself in a modified Gilbert Elliot packet loss model. The result is
 // to achieve the target packet loss rate |loss_rate|, when a packet is not
@@ -148,11 +155,11 @@
     const SdpAudioFormat& format,
     const rtc::scoped_refptr<AudioDecoderFactory>& decoder_factory)
     : audio_format_(format),
-      channels_(static_cast<size_t>(FLAG_channels)),
+      channels_(absl::GetFlag(FLAGS_channels)),
       decoded_time_ms_(0),
       decodable_time_ms_(0),
-      drift_factor_(FLAG_drift_factor),
-      packet_loss_rate_(FLAG_packet_loss_rate),
+      drift_factor_(absl::GetFlag(FLAGS_drift_factor)),
+      packet_loss_rate_(absl::GetFlag(FLAGS_packet_loss_rate)),
       block_duration_ms_(block_duration_ms),
       in_sampling_khz_(in_sampling_khz),
       out_sampling_khz_(out_sampling_khz),
@@ -160,45 +167,50 @@
           static_cast<size_t>(in_sampling_khz_ * block_duration_ms_)),
       payload_size_bytes_(0),
       max_payload_bytes_(0),
-      in_file_(new ResampleInputAudioFile(FLAG_in_filename,
-                                          FLAG_input_sample_rate,
-                                          in_sampling_khz * 1000,
-                                          FLAG_runtime_ms > 0)),
+      in_file_(
+          new ResampleInputAudioFile(absl::GetFlag(FLAGS_in_filename),
+                                     absl::GetFlag(FLAGS_input_sample_rate),
+                                     in_sampling_khz * 1000,
+                                     absl::GetFlag(FLAGS_runtime_ms) > 0)),
       rtp_generator_(
           new RtpGenerator(in_sampling_khz_, 0, 0, decodable_time_ms_)),
       total_payload_size_bytes_(0) {
   // Flag validation
-  RTC_CHECK(ValidateFilename(FLAG_in_filename, false))
+  RTC_CHECK(ValidateFilename(absl::GetFlag(FLAGS_in_filename), false))
       << "Invalid input filename.";
 
-  RTC_CHECK(FLAG_input_sample_rate == 8000 || FLAG_input_sample_rate == 16000 ||
-            FLAG_input_sample_rate == 32000 || FLAG_input_sample_rate == 48000)
+  RTC_CHECK(absl::GetFlag(FLAGS_input_sample_rate) == 8000 ||
+            absl::GetFlag(FLAGS_input_sample_rate) == 16000 ||
+            absl::GetFlag(FLAGS_input_sample_rate) == 32000 ||
+            absl::GetFlag(FLAGS_input_sample_rate) == 48000)
       << "Invalid sample rate should be 8000, 16000, 32000 or 48000 Hz.";
 
-  RTC_CHECK_EQ(FLAG_channels, 1)
+  RTC_CHECK_EQ(absl::GetFlag(FLAGS_channels), 1)
       << "Invalid number of channels, current support only 1.";
 
-  RTC_CHECK(ValidateFilename(FLAG_out_filename, true))
+  RTC_CHECK(ValidateFilename(absl::GetFlag(FLAGS_out_filename), true))
       << "Invalid output filename.";
 
-  RTC_CHECK(FLAG_packet_loss_rate >= 0 && FLAG_packet_loss_rate <= 100)
+  RTC_CHECK(absl::GetFlag(FLAGS_packet_loss_rate) >= 0 &&
+            absl::GetFlag(FLAGS_packet_loss_rate) <= 100)
       << "Invalid packet loss percentile, should be between 0 and 100.";
 
-  RTC_CHECK(FLAG_random_loss_mode >= 0 && FLAG_random_loss_mode < kLastLossMode)
+  RTC_CHECK(absl::GetFlag(FLAGS_random_loss_mode) >= 0 &&
+            absl::GetFlag(FLAGS_random_loss_mode) < kLastLossMode)
       << "Invalid random packet loss mode, should be between 0 and "
       << kLastLossMode - 1 << ".";
 
-  RTC_CHECK_GE(FLAG_burst_length, kPacketLossTimeUnitMs)
+  RTC_CHECK_GE(absl::GetFlag(FLAGS_burst_length), kPacketLossTimeUnitMs)
       << "Invalid burst length, should be greater than or equal to "
       << kPacketLossTimeUnitMs << " ms.";
 
-  RTC_CHECK_GT(FLAG_drift_factor, -0.1)
+  RTC_CHECK_GT(absl::GetFlag(FLAGS_drift_factor), -0.1)
       << "Invalid drift factor, should be greater than -0.1.";
 
-  RTC_CHECK_GE(FLAG_preload_packets, 0)
+  RTC_CHECK_GE(absl::GetFlag(FLAGS_preload_packets), 0)
       << "Invalid number of packets to preload; must be non-negative.";
 
-  const std::string out_filename = FLAG_out_filename;
+  const std::string out_filename = absl::GetFlag(FLAGS_out_filename);
   const std::string log_filename = out_filename + ".log";
   log_file_.open(log_filename.c_str(), std::ofstream::out);
   RTC_CHECK(log_file_.is_open());
@@ -283,7 +295,7 @@
   rtp_generator_->set_drift_factor(drift_factor_);
 
   int units = block_duration_ms_ / kPacketLossTimeUnitMs;
-  switch (FLAG_random_loss_mode) {
+  switch (absl::GetFlag(FLAGS_random_loss_mode)) {
     case kUniformLoss: {
       // |unit_loss_rate| is the packet loss rate for each unit time interval
       // (kPacketLossTimeUnitMs). Since a packet loss event is generated if any
@@ -297,8 +309,8 @@
       break;
     }
     case kGilbertElliotLoss: {
-      // |FLAG_burst_length| should be integer times of kPacketLossTimeUnitMs.
-      ASSERT_EQ(0, FLAG_burst_length % kPacketLossTimeUnitMs);
+      // |FLAGS_burst_length| should be integer times of kPacketLossTimeUnitMs.
+      ASSERT_EQ(0, absl::GetFlag(FLAGS_burst_length) % kPacketLossTimeUnitMs);
 
       // We do not allow 100 percent packet loss in Gilbert Elliot model, which
       // makes no sense.
@@ -316,14 +328,15 @@
       // prob_trans_00 ^ (units - 1) = (loss_rate - 1) / prob_trans_10 *
       //     prob_trans_00 + (1 - loss_rate) * (1 + 1 / prob_trans_10).
       double loss_rate = 0.01f * packet_loss_rate_;
-      double prob_trans_10 = 1.0f * kPacketLossTimeUnitMs / FLAG_burst_length;
+      double prob_trans_10 =
+          1.0f * kPacketLossTimeUnitMs / absl::GetFlag(FLAGS_burst_length);
       double prob_trans_00 = ProbTrans00Solver(units, loss_rate, prob_trans_10);
       loss_model_.reset(
           new GilbertElliotLoss(1.0f - prob_trans_10, 1.0f - prob_trans_00));
       break;
     }
     case kFixedLoss: {
-      std::istringstream loss_events_stream(FLAG_loss_events);
+      std::istringstream loss_events_stream(absl::GetFlag(FLAGS_loss_events));
       std::string loss_event_string;
       std::set<FixedLossEvent, FixedLossEventCmp> loss_events;
       while (std::getline(loss_events_stream, loss_event_string, ',')) {
@@ -415,15 +428,18 @@
 void NetEqQualityTest::Simulate() {
   int audio_size_samples;
   bool end_of_input = false;
-  int runtime_ms = FLAG_runtime_ms >= 0 ? FLAG_runtime_ms : INT_MAX;
+  int runtime_ms = absl::GetFlag(FLAGS_runtime_ms) >= 0
+                       ? absl::GetFlag(FLAGS_runtime_ms)
+                       : INT_MAX;
 
   while (!end_of_input && decoded_time_ms_ < runtime_ms) {
     // Preload the buffer if needed.
-    while (decodable_time_ms_ - FLAG_preload_packets * block_duration_ms_ <
+    while (decodable_time_ms_ -
+               absl::GetFlag(FLAGS_preload_packets) * block_duration_ms_ <
            decoded_time_ms_) {
       if (!in_file_->Read(in_size_samples_ * channels_, &in_data_[0])) {
         end_of_input = true;
-        ASSERT_TRUE(end_of_input && FLAG_runtime_ms < 0);
+        ASSERT_TRUE(end_of_input && absl::GetFlag(FLAGS_runtime_ms) < 0);
         break;
       }
       payload_.Clear();
@@ -438,8 +454,8 @@
     }
   }
   Log() << "Average bit rate was "
-        << 8.0f * total_payload_size_bytes_ / FLAG_runtime_ms << " kbps"
-        << std::endl;
+        << 8.0f * total_payload_size_bytes_ / absl::GetFlag(FLAGS_runtime_ms)
+        << " kbps" << std::endl;
 }
 
 }  // namespace test
diff --git a/modules/audio_coding/neteq/tools/neteq_quality_test.h b/modules/audio_coding/neteq/tools/neteq_quality_test.h
index e9c6dab..a8243c1 100644
--- a/modules/audio_coding/neteq/tools/neteq_quality_test.h
+++ b/modules/audio_coding/neteq/tools/neteq_quality_test.h
@@ -19,7 +19,6 @@
 #include "modules/audio_coding/neteq/tools/audio_sink.h"
 #include "modules/audio_coding/neteq/tools/input_audio_file.h"
 #include "modules/audio_coding/neteq/tools/rtp_generator.h"
-#include "rtc_base/flags.h"
 #include "test/gtest.h"
 
 namespace webrtc {
diff --git a/modules/audio_coding/neteq/tools/neteq_test_factory.cc b/modules/audio_coding/neteq/tools/neteq_test_factory.cc
index a7061eb..8147142 100644
--- a/modules/audio_coding/neteq/tools/neteq_test_factory.cc
+++ b/modules/audio_coding/neteq/tools/neteq_test_factory.cc
@@ -39,7 +39,6 @@
 #include "modules/audio_coding/neteq/tools/output_wav_file.h"
 #include "modules/audio_coding/neteq/tools/rtp_file_source.h"
 #include "rtc_base/checks.h"
-#include "rtc_base/flags.h"
 #include "rtc_base/ref_counted_object.h"
 #include "test/function_audio_decoder_factory.h"
 #include "test/testsupport/file_utils.h"
diff --git a/modules/audio_coding/neteq/tools/rtp_analyze.cc b/modules/audio_coding/neteq/tools/rtp_analyze.cc
index e71aee0..dad3750 100644
--- a/modules/audio_coding/neteq/tools/rtp_analyze.cc
+++ b/modules/audio_coding/neteq/tools/rtp_analyze.cc
@@ -18,7 +18,6 @@
 #include "absl/flags/parse.h"
 #include "modules/audio_coding/neteq/tools/packet.h"
 #include "modules/audio_coding/neteq/tools/rtp_file_source.h"
-#include "rtc_base/flags.h"
 
 ABSL_FLAG(int, red, 117, "RTP payload type for RED");
 ABSL_FLAG(int,
diff --git a/modules/audio_coding/neteq/tools/rtp_encode.cc b/modules/audio_coding/neteq/tools/rtp_encode.cc
index 0379d21..f65679d 100644
--- a/modules/audio_coding/neteq/tools/rtp_encode.cc
+++ b/modules/audio_coding/neteq/tools/rtp_encode.cc
@@ -35,7 +35,6 @@
 #include "modules/audio_coding/codecs/cng/audio_encoder_cng.h"
 #include "modules/audio_coding/include/audio_coding_module.h"
 #include "modules/audio_coding/neteq/tools/input_audio_file.h"
-#include "rtc_base/flags.h"
 #include "rtc_base/numerics/safe_conversions.h"
 
 ABSL_FLAG(bool, list_codecs, false, "Enumerate all codecs");