Update a ton of audio code to use size_t more correctly and in general reduce

webrtc/modules/audio_coding/codecs/pcm16b/pcm16b.c

Index: webrtc/modules/audio_coding/codecs/pcm16b/pcm16b.c
diff --git a/webrtc/modules/audio_coding/codecs/pcm16b/pcm16b.c b/webrtc/modules/audio_coding/codecs/pcm16b/pcm16b.c
index b6de0b5e67b2acca0fa8e8bbd5d4a3ed7a52d36e..120c79052bd9bfdae1e739d436f98b0cfc559b28 100644
--- a/webrtc/modules/audio_coding/codecs/pcm16b/pcm16b.c
+++ b/webrtc/modules/audio_coding/codecs/pcm16b/pcm16b.c
@@ -12,10 +12,10 @@
 
 #include "webrtc/typedefs.h"
 
-int16_t WebRtcPcm16b_Encode(const int16_t* speech,
-                            int16_t len,
-                            uint8_t* encoded) {
-  int i;
+size_t WebRtcPcm16b_Encode(const int16_t* speech,
+                           size_t len,
+                           uint8_t* encoded) {
+  size_t i;
   for (i = 0; i < len; ++i) {
     uint16_t s = speech[i];
     encoded[2 * i] = s >> 8;
@@ -24,10 +24,10 @@ int16_t WebRtcPcm16b_Encode(const int16_t* speech,
   return 2 * len;
 }
 
-int16_t WebRtcPcm16b_Decode(const uint8_t* encoded,
-                            int16_t len,
-                            int16_t* speech) {
-  int i;
+size_t WebRtcPcm16b_Decode(const uint8_t* encoded,
+                           size_t len,
+                           int16_t* speech) {
+  size_t i;
   for (i = 0; i < len / 2; ++i)
     speech[i] = encoded[2 * i] << 8 | encoded[2 * i + 1];
   return len / 2;