Deprecate kIamfConfigObus (youtube#2372)

The kIamfConfigObus enum was previously added to allow IAMF metadata to
be written to Starboard in a future decoder implementation. The design
changed and kIamfConfigObus will no longer be used.

b/271301103

starboard/CHANGELOG.md

@@ -57,10 +57,6 @@ deprecated.
 The APIs defined in `starboard/image.h` are no longer used and have been
 deprecated.
 
-### Add a new enum `kIamfConfigObus` to `SbPlayerSampleSideDataType` in `starboard/player.h`
-This value allows IAMF samples to be written to Starboard along with IAMF
-Config OBUs as side data.
-
 ### Deprecated SbStringScan and SbStringScanF
 The APIs defined in `starboard/string.h` are deprecated and the standard API `vsscanf` and `sscanf` are used instead.
 

starboard/player.h

@@ -144,12 +144,6 @@ typedef enum SbPlayerSampleSideDataType {
   // The first 8 bytes of the data contains the value of BlockAddID in big
   // endian format, followed by the content of BlockAdditional.
   kMatroskaBlockAdditional,
-#if SB_API_VERSION >= 16
-  // The config OBUs located in the IASampleEntry Box in the MP4 container, as
-  // specified in
-  // https://aomediacodec.github.io/iamf/#standalone-descriptor-obus.
-  kIamfConfigObus,
-#endif  // SB_API_VERSION >= 16
 } SbPlayerSampleSideDataType;
 
 // Side data accompanied with |SbPlayerSampleInfo|, it can be arbitrary binary