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/codecs/ilbc/defines.h b/webrtc/modules/audio_coding/codecs/ilbc/defines.h
index 2d37e52..5fcd4a0 100644
--- a/webrtc/modules/audio_coding/codecs/ilbc/defines.h
+++ b/webrtc/modules/audio_coding/codecs/ilbc/defines.h
@@ -121,11 +121,11 @@
   int16_t lsf[LSF_NSPLIT*LPC_N_MAX];
   int16_t cb_index[CB_NSTAGES*(NASUB_MAX+1)];  /* First CB_NSTAGES values contains extra CB index */
   int16_t gain_index[CB_NSTAGES*(NASUB_MAX+1)]; /* First CB_NSTAGES values contains extra CB gain */
-  int16_t idxForMax;
+  size_t idxForMax;
   int16_t state_first;
   int16_t idxVec[STATE_SHORT_LEN_30MS];
   int16_t firstbits;
-  int16_t startIdx;
+  size_t startIdx;
 } iLBC_bits;
 
 /* type definition encoder instance */
@@ -135,12 +135,12 @@
   int16_t mode;
 
   /* basic parameters for different frame sizes */
-  int16_t blockl;
-  int16_t nsub;
+  size_t blockl;
+  size_t nsub;
   int16_t nasub;
-  int16_t no_of_bytes, no_of_words;
+  size_t no_of_bytes, no_of_words;
   int16_t lpc_n;
-  int16_t state_short_len;
+  size_t state_short_len;
 
   /* analysis filter state */
   int16_t anaMem[LPC_FILTERORDER];
@@ -164,7 +164,7 @@
   int16_t Nfor_flag;
   int16_t Nback_flag;
   int16_t start_pos;
-  int16_t diff;
+  size_t diff;
 #endif
 
 } IlbcEncoder;
@@ -176,12 +176,12 @@
   int16_t mode;
 
   /* basic parameters for different frame sizes */
-  int16_t blockl;
-  int16_t nsub;
+  size_t blockl;
+  size_t nsub;
   int16_t nasub;
-  int16_t no_of_bytes, no_of_words;
+  size_t no_of_bytes, no_of_words;
   int16_t lpc_n;
-  int16_t state_short_len;
+  size_t state_short_len;
 
   /* synthesis filter state */
   int16_t syntMem[LPC_FILTERORDER];
@@ -190,14 +190,15 @@
   int16_t lsfdeqold[LPC_FILTERORDER];
 
   /* pitch lag estimated in enhancer and used in PLC */
-  int last_lag;
+  size_t last_lag;
 
   /* PLC state information */
   int consPLICount, prev_enh_pl;
   int16_t perSquare;
 
   int16_t prevScale, prevPLI;
-  int16_t prevLag, prevLpc[LPC_FILTERORDER+1];
+  size_t prevLag;
+  int16_t prevLpc[LPC_FILTERORDER+1];
   int16_t prevResidual[NSUB_MAX*SUBL];
   int16_t seed;