[NOT FOR REVIEW] Convert channel counts to size_t.

webrtc/modules/audio_coding/codecs/cng/audio_encoder_cng.cc

 /*
  *  Copyright (c) 2014 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 61 matching lines @@
 }
 
 int AudioEncoderCng::SampleRateHz() const {
   return speech_encoder_->SampleRateHz();
 }
 
 int AudioEncoderCng::RtpTimestampRateHz() const {
   return speech_encoder_->RtpTimestampRateHz();
 }
 
-int AudioEncoderCng::NumChannels() const {
+size_t AudioEncoderCng::NumChannels() const {
   return 1;
 }
 
 size_t AudioEncoderCng::MaxEncodedBytes() const {
   const size_t max_encoded_bytes_active = speech_encoder_->MaxEncodedBytes();
   const size_t max_encoded_bytes_passive =
       rtc::CheckedDivExact(kMaxFrameSizeMs, 10) * SamplesPer10msFrame();
   return std::max(max_encoded_bytes_active, max_encoded_bytes_passive);
 }
 
@@ skipping 140 matching lines @@
     }
   }
   return info;
 }
 
 size_t AudioEncoderCng::SamplesPer10msFrame() const {
   return rtc::CheckedDivExact(10 * SampleRateHz(), 1000);
 }
 
 }  // namespace webrtc