Convert channel counts to size_t.

webrtc/voice_engine/utility.h

Index: webrtc/voice_engine/utility.h
diff --git a/webrtc/voice_engine/utility.h b/webrtc/voice_engine/utility.h
index cc44533665f6d811fa9934e0427d47c9beee142a..4139f05cfddae809543f2a64b100d28fc98b3284 100644
--- a/webrtc/voice_engine/utility.h
+++ b/webrtc/voice_engine/utility.h
@@ -40,15 +40,15 @@ void RemixAndResample(const AudioFrame& src_frame,
 // parameters.
 void RemixAndResample(const int16_t* src_data,
                       size_t samples_per_channel,
-                      int num_channels,
+                      size_t num_channels,
                       int sample_rate_hz,
                       PushResampler<int16_t>* resampler,
                       AudioFrame* dst_frame);
 
 void MixWithSat(int16_t target[],
-                int target_channel,
+                size_t target_channel,
                 const int16_t source[],
-                int source_channel,
+                size_t source_channel,
                 size_t source_len);
 
 }  // namespace voe