[NOT FOR REVIEW] Convert channel counts to size_t.

webrtc/modules/audio_processing/audio_processing_impl.h

 /*
  *  Copyright (c) 2012 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 53 matching lines @@
                  ChannelLayout input_layout,
                  ChannelLayout output_layout,
                  ChannelLayout reverse_layout) override;
   int Initialize(const ProcessingConfig& processing_config) override;
   void SetExtraOptions(const Config& config) override;
   int set_sample_rate_hz(int rate) override;
   int input_sample_rate_hz() const override;
   int sample_rate_hz() const override;
   int proc_sample_rate_hz() const override;
   int proc_split_sample_rate_hz() const override;
-  int num_input_channels() const override;
-  int num_output_channels() const override;
-  int num_reverse_channels() const override;
+  size_t num_input_channels() const override;
+  size_t num_output_channels() const override;
+  size_t num_reverse_channels() const override;
   void set_output_will_be_muted(bool muted) override;
   bool output_will_be_muted() const override;
   int ProcessStream(AudioFrame* frame) override;
   int ProcessStream(const float* const* src,
                     size_t samples_per_channel,
                     int input_sample_rate_hz,
                     ChannelLayout input_layout,
                     int output_sample_rate_hz,
                     ChannelLayout output_layout,
                     float* const* dest) override;
@@ skipping 102 matching lines @@
   bool transient_suppressor_enabled_;
   rtc::scoped_ptr<TransientSuppressor> transient_suppressor_;
   const bool beamformer_enabled_;
   rtc::scoped_ptr<Beamformer<float>> beamformer_;
   const std::vector<Point> array_geometry_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_PROCESSING_AUDIO_PROCESSING_IMPL_H_