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_processing/include/audio_processing.h b/webrtc/modules/audio_processing/include/audio_processing.h
index fd91bfa..445d5c8 100644
--- a/webrtc/modules/audio_processing/include/audio_processing.h
+++ b/webrtc/modules/audio_processing/include/audio_processing.h
@@ -311,7 +311,7 @@
   //
   // TODO(mgraczyk): Remove once clients are updated to use the new interface.
   virtual int ProcessStream(const float* const* src,
-                            int samples_per_channel,
+                            size_t samples_per_channel,
                             int input_sample_rate_hz,
                             ChannelLayout input_layout,
                             int output_sample_rate_hz,
@@ -357,7 +357,7 @@
   // of |data| points to a channel buffer, arranged according to |layout|.
   // TODO(mgraczyk): Remove once clients are updated to use the new interface.
   virtual int AnalyzeReverseStream(const float* const* data,
-                                   int samples_per_channel,
+                                   size_t samples_per_channel,
                                    int rev_sample_rate_hz,
                                    ChannelLayout layout) = 0;
 
@@ -510,8 +510,8 @@
   int num_channels() const { return num_channels_; }
 
   bool has_keyboard() const { return has_keyboard_; }
-  int num_frames() const { return num_frames_; }
-  int num_samples() const { return num_channels_ * num_frames_; }
+  size_t num_frames() const { return num_frames_; }
+  size_t num_samples() const { return num_channels_ * num_frames_; }
 
   bool operator==(const StreamConfig& other) const {
     return sample_rate_hz_ == other.sample_rate_hz_ &&
@@ -522,14 +522,15 @@
   bool operator!=(const StreamConfig& other) const { return !(*this == other); }
 
  private:
-  static int calculate_frames(int sample_rate_hz) {
-    return AudioProcessing::kChunkSizeMs * sample_rate_hz / 1000;
+  static size_t calculate_frames(int sample_rate_hz) {
+    return static_cast<size_t>(
+        AudioProcessing::kChunkSizeMs * sample_rate_hz / 1000);
   }
 
   int sample_rate_hz_;
   int num_channels_;
   bool has_keyboard_;
-  int num_frames_;
+  size_t num_frames_;
 };
 
 class ProcessingConfig {