[NOT FOR REVIEW] Convert channel counts to size_t.

webrtc/modules/audio_coding/main/acm2/acm_receiver.cc

Index: webrtc/modules/audio_coding/main/acm2/acm_receiver.cc
diff --git a/webrtc/modules/audio_coding/main/acm2/acm_receiver.cc b/webrtc/modules/audio_coding/main/acm2/acm_receiver.cc
index a21b32b9211d84b5dea99f66593c537b58d39852..88fb6202a2ea47ddc9a2ef5b794349a05e76bc6b 100644
--- a/webrtc/modules/audio_coding/main/acm2/acm_receiver.cc
+++ b/webrtc/modules/audio_coding/main/acm2/acm_receiver.cc
@@ -345,7 +345,7 @@ int AcmReceiver::InsertPacket(const WebRtcRTPHeader& rtp_header,
 int AcmReceiver::GetAudio(int desired_freq_hz, AudioFrame* audio_frame) {
   enum NetEqOutputType type;
   size_t samples_per_channel;
-  int num_channels;
+  size_t num_channels;
   bool return_silence = false;
 
   {
@@ -475,7 +475,7 @@ int AcmReceiver::GetAudio(int desired_freq_hz, AudioFrame* audio_frame) {
 
 int32_t AcmReceiver::AddCodec(int acm_codec_id,
                               uint8_t payload_type,
-                              int channels,
+                              size_t channels,
                               int sample_rate_hz,
                               AudioDecoder* audio_decoder) {
   assert(acm_codec_id >= 0);