Correctly handle the error case where the CodecId has a negative value

webrtc/modules/audio_coding/main/acm2/rent_a_codec.h

Index: webrtc/modules/audio_coding/main/acm2/rent_a_codec.h
diff --git a/webrtc/modules/audio_coding/main/acm2/rent_a_codec.h b/webrtc/modules/audio_coding/main/acm2/rent_a_codec.h
index 24ae121a478c44f10f339d81afd035c71243029b..dc441249e20ff5c8168f35d07feec82c523b96e3 100644
--- a/webrtc/modules/audio_coding/main/acm2/rent_a_codec.h
+++ b/webrtc/modules/audio_coding/main/acm2/rent_a_codec.h
@@ -132,9 +132,9 @@ class RentACodec {
   }
 
   static inline rtc::Maybe<int> CodecIndexFromId(CodecId codec_id) {
-    const int i = static_cast<int>(codec_id);
-    return i < static_cast<int>(NumberOfCodecs()) ? rtc::Maybe<int>(i)
-                                                  : rtc::Maybe<int>();
+    const size_t i = static_cast<size_t>(codec_id);

[hlundin-webrtc, 2015/11/04 11:03:42]

No sir, I didn't like it.
I prefer augmenting the original conditional instead of casting and re-casting:
return i>= 0 && i < static_cast<int>(NumberOfCodecs()) ? ...;

[kwiberg-webrtc, 2015/11/04 14:27:59]

Done.

+    return i < NumberOfCodecs() ? rtc::Maybe<int>(static_cast<int>(i))
+                                : rtc::Maybe<int>();
   }
 
   static inline rtc::Maybe<CodecId> CodecIdFromIndex(int codec_index) {