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..50d8c54ab480cfb004810ddecf0fb6ecf13e8fb0 100644
--- a/webrtc/modules/audio_coding/main/acm2/rent_a_codec.h
+++ b/webrtc/modules/audio_coding/main/acm2/rent_a_codec.h
@@ -133,8 +133,8 @@ 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>();
+    return i >= 0 && i < static_cast<int>(NumberOfCodecs()) ? rtc::Maybe<int>(i)
+                                                            : rtc::Maybe<int>();
   }
 
   static inline rtc::Maybe<CodecId> CodecIdFromIndex(int codec_index) {