The file webrtc/voice_engine_configurations.h (formerly webrtc/engine_configurations.h) is going to be deleted.
The file holds a number of pre-processor defines which are always set. The one exception is WEBRTC_VOICE_ENGINE_TYPING_DETECTION which will be moved to webrtc/voice_engine/transmit_mixer.h. Code paths that can no longer be reached due to this change will also be removed.
The work is tracked in issue 6506. It will be done in steps, aiming at finally deleting the file itself in two weeks.