Upconvert various types to int.

Per comments from HL/kwiberg on https://webrtc-codereview.appspot.com/42569004 , when there is existing usage of mixed types (int16_t, int, etc.), we'd prefer to standardize on larger types like int and phase out use of int16_t.

Specifically, "Using int16 just because we're sure all reasonable values will fit in 16 bits isn't usually meaningful in C."

This converts some existing uses of int16_t (and, in a few cases, other types such as uint16_t) to int (or, in a few places, int32_t).  Other locations will be converted to size_t in a separate change.

BUG=none
R=andrew@webrtc.org, kwiberg@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/54629004

Cr-Commit-Position: refs/heads/master@{#9405}

webrtc/modules/audio_coding/codecs/ilbc/init_encode.h

@@ -25,7 +25,7 @@
  *  Initiation of encoder instance.
  *---------------------------------------------------------------*/
 
-int16_t WebRtcIlbcfix_InitEncode(  /* (o) Number of bytes encoded */
+int WebRtcIlbcfix_InitEncode(  /* (o) Number of bytes encoded */
     IlbcEncoder *iLBCenc_inst, /* (i/o) Encoder instance */
     int16_t mode     /* (i) frame size mode */
                                          );