Merge pull request #700 from tguilbert-google/audio_encoder_bitrate_mode

Add AudioEncoderConfig.bitrateMode default

Author: aboba

index.src.html

@@ -2040,7 +2040,7 @@
   [EnforceRange] unsigned long sampleRate;
   [EnforceRange] unsigned long numberOfChannels;
   [EnforceRange] unsigned long long bitrate;
-  BitrateMode bitrateMode;
+  BitrateMode bitrateMode = "variable";
 };
 </xmp>