[NOT FOR REVIEW] Convert channel counts to size_t.

talk/media/base/codec.h

Index: talk/media/base/codec.h
diff --git a/talk/media/base/codec.h b/talk/media/base/codec.h
index 3bb08e7c7a926e26b774d61d48f41df10e0cb76e..5f4bb005d8307c04251091506796952092afe76e 100644
--- a/talk/media/base/codec.h
+++ b/talk/media/base/codec.h
@@ -128,10 +128,10 @@ struct Codec {
 
 struct AudioCodec : public Codec {
   int bitrate;
-  int channels;
+  size_t channels;
 
   // Creates a codec with the given parameters.
-  AudioCodec(int pt, const std::string& nm, int cr, int br, int cs, int pr);
+  AudioCodec(int pt, const std::string& nm, int cr, int br, size_t cs, int pr);
   // Creates an empty codec.
   AudioCodec();
   AudioCodec(const AudioCodec& c);