message: Make VideoStreamEncoderInterface::SetFecControllerOverride pure virtual
  Clean-up after CL
  Cr-Commit-Position: refs/heads/master@{#28424}
diff: @@ -100,10 +100,8 @@ class VideoStreamEncoderInterface : public rtc::VideoSinkInterface<VideoFrame> {
  // Set a FecControllerOverride, through which the encoder may override
  // decisions made by FecController.
  - // TODO(bugs.webrtc.org/10769): Update downstream projects and then make this
  - // pure-virtual.
  virtual void SetFecControllerOverride(
  - FecControllerOverride* fec_controller_override) {}
  + FecControllerOverride* fec_controller_override) = 0;
  // Creates and configures an encoder with the given |config|. The
  // |max_data_payload_length| is used to support single NAL unit
  