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/system_wrappers/interface/aligned_array.h b/webrtc/system_wrappers/interface/aligned_array.h
index 8278af2..3648c7c 100644
--- a/webrtc/system_wrappers/interface/aligned_array.h
+++ b/webrtc/system_wrappers/interface/aligned_array.h
@@ -20,7 +20,7 @@
 // aligned to the given byte alignment.
 template<typename T> class AlignedArray {
  public:
-  AlignedArray(int rows, int cols, int alignment)
+  AlignedArray(int rows, size_t cols, int alignment)
       : rows_(rows),
         cols_(cols),
         alignment_(alignment) {
@@ -58,12 +58,12 @@
     return head_row_[row];
   }
 
-  T& At(int row, int col) {
+  T& At(int row, size_t col) {
     CHECK_LE(col, cols_);
     return Row(row)[col];
   }
 
-  const T& At(int row, int col) const {
+  const T& At(int row, size_t col) const {
     CHECK_LE(col, cols_);
     return Row(row)[col];
   }
@@ -72,13 +72,13 @@
     return rows_;
   }
 
-  int cols() const {
+  size_t cols() const {
     return cols_;
   }
 
  private:
   int rows_;
-  int cols_;
+  size_t cols_;
   int alignment_;
   T** head_row_;
 };