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

webrtc/common_audio/audio_util.cc

 /*
  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 23 matching lines @@
     dest[i] = FloatToFloatS16(src[i]);
 }
 
 void FloatS16ToFloat(const float* src, size_t size, float* dest) {
   for (size_t i = 0; i < size; ++i)
     dest[i] = FloatS16ToFloat(src[i]);
 }
 
 template <>
 void DownmixInterleavedToMono<int16_t>(const int16_t* interleaved,
-                                       int num_frames,
+                                       size_t num_frames,
                                        int num_channels,
                                        int16_t* deinterleaved) {
   DownmixInterleavedToMonoImpl<int16_t, int32_t>(interleaved, num_frames,
                                                  num_channels, deinterleaved);
 }
 
 }  // namespace webrtc