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 83 matching lines @@
   int ProcessReverseStream(const float* const* src,
                            const StreamConfig& reverse_input_config,
                            const StreamConfig& reverse_output_config,
                            float* const* dest) override;
 
   // Methods only accessed from APM submodules or
   // from AudioProcessing tests in a single-threaded manner.
   // Hence there is no need for locks in these.
   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;
   int stream_delay_ms() const override;
   bool was_stream_delay_set() const override
       EXCLUSIVE_LOCKS_REQUIRED(crit_capture_);
 
   // Methods returning pointers to APM submodules.
   // No locks are aquired in those, as those locks
   // would offer no protection (the submodules are
   // created only once in a single-treaded manner
   // during APM creation).
   EchoCancellation* echo_cancellation() const override;
@@ skipping 215 matching lines @@
 
   struct ApmRenderState {
     rtc::scoped_ptr<AudioConverter> render_converter;
     rtc::scoped_ptr<AudioBuffer> render_audio;
   } render_ GUARDED_BY(crit_render_);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_PROCESSING_AUDIO_PROCESSING_IMPL_H_