Update a ton of audio code to use size_t more correctly and in general reduce
use of int16_t/uint16_t.

This is the upshot of a recommendation by henrik.lundin and kwiberg on an original small change ( https://webrtc-codereview.appspot.com/42569004/#ps1 ) to stop using int16_t just because values could fit in it, and is similar in nature to a previous "mass change to use size_t more" ( https://webrtc-codereview.appspot.com/23129004/ ) which also needed to be split up for review but to land all at once, since, like adding "const", such changes tend to cause a lot of transitive effects.

This was be reviewed and approved in pieces:
https://codereview.webrtc.org/1224093003
https://codereview.webrtc.org/1224123002
https://codereview.webrtc.org/1224163002
https://codereview.webrtc.org/1225133003
https://codereview.webrtc.org/1225173002
https://codereview.webrtc.org/1227163003
https://codereview.webrtc.org/1227203003
https://codereview.webrtc.org/1227213002
https://codereview.webrtc.org/1227893002
https://codereview.webrtc.org/1228793004
https://codereview.webrtc.org/1228803003
https://codereview.webrtc.org/1228823002
https://codereview.webrtc.org/1228823003
https://codereview.webrtc.org/1228843002
https://codereview.webrtc.org/1230693002
https://codereview.webrtc.org/1231713002

The change is being landed as TBR to all the folks who reviewed the above.

BUG=chromium:81439
TEST=none
R=andrew@webrtc.org, pbos@webrtc.org
TBR=aluebs, andrew, asapersson, henrika, hlundin, jan.skoglund, kwiberg, minyue, pbos, pthatcher

Review URL: https://codereview.webrtc.org/1230503003 .

Cr-Commit-Position: refs/heads/master@{#9768}
diff --git a/webrtc/modules/audio_coding/neteq/neteq_unittest.cc b/webrtc/modules/audio_coding/neteq/neteq_unittest.cc
index 7137a68..03fde53 100644
--- a/webrtc/modules/audio_coding/neteq/neteq_unittest.cc
+++ b/webrtc/modules/audio_coding/neteq/neteq_unittest.cc
@@ -37,16 +37,16 @@
 
 namespace webrtc {
 
-static bool IsAllZero(const int16_t* buf, int buf_length) {
+static bool IsAllZero(const int16_t* buf, size_t buf_length) {
   bool all_zero = true;
-  for (int n = 0; n < buf_length && all_zero; ++n)
+  for (size_t n = 0; n < buf_length && all_zero; ++n)
     all_zero = buf[n] == 0;
   return all_zero;
 }
 
-static bool IsAllNonZero(const int16_t* buf, int buf_length) {
+static bool IsAllNonZero(const int16_t* buf, size_t buf_length) {
   bool all_non_zero = true;
-  for (int n = 0; n < buf_length && all_non_zero; ++n)
+  for (size_t n = 0; n < buf_length && all_non_zero; ++n)
     all_non_zero = buf[n] != 0;
   return all_non_zero;
 }
@@ -172,7 +172,8 @@
     ASSERT_EQ(stats.preemptive_rate, ref_stats.preemptive_rate);
     ASSERT_EQ(stats.accelerate_rate, ref_stats.accelerate_rate);
     ASSERT_EQ(stats.clockdrift_ppm, ref_stats.clockdrift_ppm);
-    ASSERT_EQ(stats.added_zero_samples, ref_stats.added_zero_samples);
+    ASSERT_EQ(stats.added_zero_samples,
+              static_cast<size_t>(ref_stats.added_zero_samples));
     ASSERT_EQ(stats.secondary_decoded_rate, 0);
     ASSERT_LE(stats.speech_expand_rate, ref_stats.expand_rate);
   }
@@ -220,9 +221,9 @@
   // NetEQ must be polled for data once every 10 ms. Thus, neither of the
   // constants below can be changed.
   static const int kTimeStepMs = 10;
-  static const int kBlockSize8kHz = kTimeStepMs * 8;
-  static const int kBlockSize16kHz = kTimeStepMs * 16;
-  static const int kBlockSize32kHz = kTimeStepMs * 32;
+  static const size_t kBlockSize8kHz = kTimeStepMs * 8;
+  static const size_t kBlockSize16kHz = kTimeStepMs * 16;
+  static const size_t kBlockSize32kHz = kTimeStepMs * 32;
   static const size_t kMaxBlockSize = kBlockSize32kHz;
   static const int kInitSampleRateHz = 8000;
 
@@ -232,7 +233,7 @@
   void SelectDecoders(NetEqDecoder* used_codec);
   void LoadDecoders();
   void OpenInputFile(const std::string &rtp_file);
-  void Process(int* out_len);
+  void Process(size_t* out_len);
   void DecodeAndCompare(const std::string& rtp_file,
                         const std::string& ref_file,
                         const std::string& stat_ref_file,
@@ -272,9 +273,9 @@
 
 // Allocating the static const so that it can be passed by reference.
 const int NetEqDecodingTest::kTimeStepMs;
-const int NetEqDecodingTest::kBlockSize8kHz;
-const int NetEqDecodingTest::kBlockSize16kHz;
-const int NetEqDecodingTest::kBlockSize32kHz;
+const size_t NetEqDecodingTest::kBlockSize8kHz;
+const size_t NetEqDecodingTest::kBlockSize16kHz;
+const size_t NetEqDecodingTest::kBlockSize32kHz;
 const size_t NetEqDecodingTest::kMaxBlockSize;
 const int NetEqDecodingTest::kInitSampleRateHz;
 
@@ -334,7 +335,7 @@
   rtp_source_.reset(test::RtpFileSource::Create(rtp_file));
 }
 
-void NetEqDecodingTest::Process(int* out_len) {
+void NetEqDecodingTest::Process(size_t* out_len) {
   // Check if time to receive.
   while (packet_ && sim_clock_ >= packet_->time_ms()) {
     if (packet_->payload_length_bytes() > 0) {
@@ -358,7 +359,7 @@
   ASSERT_TRUE((*out_len == kBlockSize8kHz) ||
               (*out_len == kBlockSize16kHz) ||
               (*out_len == kBlockSize32kHz));
-  output_sample_rate_ = *out_len / 10 * 1000;
+  output_sample_rate_ = static_cast<int>(*out_len / 10 * 1000);
 
   // Increase time.
   sim_clock_ += kTimeStepMs;
@@ -394,7 +395,7 @@
     std::ostringstream ss;
     ss << "Lap number " << i++ << " in DecodeAndCompare while loop";
     SCOPED_TRACE(ss.str());  // Print out the parameter values on failure.
-    int out_len = 0;
+    size_t out_len = 0;
     ASSERT_NO_FATAL_FAILURE(Process(&out_len));
     ASSERT_NO_FATAL_FAILURE(ref_files.ProcessReference(out_data_, out_len));
 
@@ -498,7 +499,7 @@
   }
   // Pull out all data.
   for (size_t i = 0; i < num_frames; ++i) {
-    int out_len;
+    size_t out_len;
     int num_channels;
     NetEqOutputType type;
     ASSERT_EQ(0, neteq_->GetAudio(kMaxBlockSize, out_data_, &out_len,
@@ -536,7 +537,7 @@
         rtp_info,
         reinterpret_cast<uint8_t*>(payload),
         kPayloadBytes, 0));
-    int out_len;
+    size_t out_len;
     int num_channels;
     NetEqOutputType type;
     ASSERT_EQ(0, neteq_->GetAudio(kMaxBlockSize, out_data_, &out_len,
@@ -566,7 +567,7 @@
     }
 
     // Pull out data once.
-    int out_len;
+    size_t out_len;
     int num_channels;
     NetEqOutputType type;
     ASSERT_EQ(0, neteq_->GetAudio(kMaxBlockSize, out_data_, &out_len,
@@ -597,7 +598,7 @@
     }
 
     // Pull out data once.
-    int out_len;
+    size_t out_len;
     int num_channels;
     NetEqOutputType type;
     ASSERT_EQ(0, neteq_->GetAudio(kMaxBlockSize, out_data_, &out_len,
@@ -622,7 +623,7 @@
   const size_t kPayloadBytes = kSamples * 2;
   double next_input_time_ms = 0.0;
   double t_ms;
-  int out_len;
+  size_t out_len;
   int num_channels;
   NetEqOutputType type;
 
@@ -854,7 +855,7 @@
     out_data_[i] = 1;
   }
   int num_channels;
-  int samples_per_channel;
+  size_t samples_per_channel;
   EXPECT_EQ(NetEq::kFail,
             neteq_->GetAudio(kMaxBlockSize, out_data_,
                              &samples_per_channel, &num_channels, &type));
@@ -887,7 +888,7 @@
     out_data_[i] = 1;
   }
   int num_channels;
-  int samples_per_channel;
+  size_t samples_per_channel;
   EXPECT_EQ(0, neteq_->GetAudio(kMaxBlockSize, out_data_,
                                 &samples_per_channel,
                                 &num_channels, &type));
@@ -908,7 +909,7 @@
                              bool should_be_faded) = 0;
 
   void CheckBgn(int sampling_rate_hz) {
-    int16_t expected_samples_per_channel = 0;
+    size_t expected_samples_per_channel = 0;
     uint8_t payload_type = 0xFF;  // Invalid.
     if (sampling_rate_hz == 8000) {
       expected_samples_per_channel = kBlockSize8kHz;
@@ -932,7 +933,7 @@
     ASSERT_TRUE(input.Init(
         webrtc::test::ResourcePath("audio_coding/testfile32kHz", "pcm"),
         10 * sampling_rate_hz,  // Max 10 seconds loop length.
-        static_cast<size_t>(expected_samples_per_channel)));
+        expected_samples_per_channel));
 
     // Payload of 10 ms of PCM16 32 kHz.
     uint8_t payload[kBlockSize32kHz * sizeof(int16_t)];
@@ -941,19 +942,18 @@
     rtp_info.header.payloadType = payload_type;
 
     int number_channels = 0;
-    int samples_per_channel = 0;
+    size_t samples_per_channel = 0;
 
     uint32_t receive_timestamp = 0;
     for (int n = 0; n < 10; ++n) {  // Insert few packets and get audio.
-      int16_t enc_len_bytes = WebRtcPcm16b_Encode(
+      size_t enc_len_bytes = WebRtcPcm16b_Encode(
           input.GetNextBlock(), expected_samples_per_channel, payload);
       ASSERT_EQ(enc_len_bytes, expected_samples_per_channel * 2);
 
       number_channels = 0;
       samples_per_channel = 0;
       ASSERT_EQ(0,
-                neteq_->InsertPacket(rtp_info, payload,
-                                     static_cast<size_t>(enc_len_bytes),
+                neteq_->InsertPacket(rtp_info, payload, enc_len_bytes,
                                      receive_timestamp));
       ASSERT_EQ(0,
                 neteq_->GetAudio(kBlockSize32kHz,
@@ -1009,7 +1009,7 @@
       if (type == kOutputPLCtoCNG) {
         plc_to_cng = true;
         double sum_squared = 0;
-        for (int k = 0; k < number_channels * samples_per_channel; ++k)
+        for (size_t k = 0; k < number_channels * samples_per_channel; ++k)
           sum_squared += output[k] * output[k];
         TestCondition(sum_squared, n > kFadingThreshold);
       } else {
@@ -1168,7 +1168,7 @@
   // actual decoded values.
   NetEqOutputType output_type;
   int num_channels;
-  int samples_per_channel;
+  size_t samples_per_channel;
   uint32_t receive_timestamp = 0;
   for (int n = 0; n < 100; ++n) {
     ASSERT_EQ(0, neteq_->InsertPacket(rtp_info, payload, kPayloadBytes,
@@ -1246,7 +1246,7 @@
   // actual decoded values.
   NetEqOutputType output_type;
   int num_channels;
-  int samples_per_channel;
+  size_t samples_per_channel;
   uint32_t receive_timestamp = 0;
   int algorithmic_frame_delay = algorithmic_delay_ms_ / 10 + 1;
   for (int n = 0; n < algorithmic_frame_delay; ++n) {
@@ -1315,7 +1315,7 @@
   double next_input_time_ms = 0.0;
   int16_t decoded[kBlockSize16kHz];
   int num_channels;
-  int samples_per_channel;
+  size_t samples_per_channel;
   NetEqOutputType output_type;
   uint32_t receive_timestamp = 0;
 
@@ -1418,7 +1418,7 @@
       algorithmic_delay_ms_ * kSampleRateKhz, 5 * kSampleRateKhz / 8);
   // Insert three speech packets. Three are needed to get the frame length
   // correct.
-  int out_len;
+  size_t out_len;
   int num_channels;
   NetEqOutputType type;
   uint8_t payload[kPayloadBytes] = {0};
@@ -1515,7 +1515,7 @@
   timestamp += kCngPeriodSamples;
 
   // Pull audio once and make sure CNG is played.
-  int out_len;
+  size_t out_len;
   int num_channels;
   NetEqOutputType type;
   ASSERT_EQ(0, neteq_->GetAudio(kMaxBlockSize, out_data_, &out_len,