[NOT FOR REVIEW] Convert channel counts to size_t.

webrtc/modules/audio_coding/codecs/g711/audio_encoder_pcm.cc

Index: webrtc/modules/audio_coding/codecs/g711/audio_encoder_pcm.cc
diff --git a/webrtc/modules/audio_coding/codecs/g711/audio_encoder_pcm.cc b/webrtc/modules/audio_coding/codecs/g711/audio_encoder_pcm.cc
index ba5959dbcd5c32571e7ab53db0af2c1f4034437f..127751c5ddb4e1b930c2d041e8d915e568f209f7 100644
--- a/webrtc/modules/audio_coding/codecs/g711/audio_encoder_pcm.cc
+++ b/webrtc/modules/audio_coding/codecs/g711/audio_encoder_pcm.cc
@@ -19,11 +19,13 @@
 namespace webrtc {
 
 namespace {
-int16_t NumSamplesPerFrame(int num_channels,
+int16_t NumSamplesPerFrame(size_t num_channels,
                            int frame_size_ms,
                            int sample_rate_hz) {
-  int samples_per_frame = num_channels * frame_size_ms * sample_rate_hz / 1000;
-  CHECK_LE(samples_per_frame, std::numeric_limits<int16_t>::max())
+  size_t samples_per_frame =
+      num_channels * frame_size_ms * sample_rate_hz / 1000;
+  CHECK_LE(samples_per_frame,
+           static_cast<size_t>(std::numeric_limits<int16_t>::max()))
       << "Frame size too large.";
   return static_cast<int16_t>(samples_per_frame);
 }
@@ -56,7 +58,7 @@ int AudioEncoderPcm::SampleRateHz() const {
   return sample_rate_hz_;
 }
 
-int AudioEncoderPcm::NumChannels() const {
+size_t AudioEncoderPcm::NumChannels() const {
   return num_channels_;
 }