Remove webrtc::VideoDecoder::PrefersLateDecoding.

This is just general cleanup.

The assumed behavior is late decoding, and this function is not used to make any decision (except in the deprecated jitter buffer).

Bug: webrtc:12271
Change-Id: Ifb48186d55903f068f25e44c5f73e7a724f6f456
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/200804
Commit-Queue: Philip Eliasson <philipel@webrtc.org>
Reviewed-by: Sami Kalliomäki <sakal@webrtc.org>
Reviewed-by: Christoffer Rodbro <crodbro@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32940}

modules/video_coding/decoder_database.h

@@ -59,10 +59,6 @@ class VCMDecoderDataBase {
       const VCMEncodedFrame& frame,
       VCMDecodedFrameCallback* decoded_frame_callback);
 
-  // Returns true if the currently active decoder prefer to decode frames late.
-  // That means that frames must be decoded near the render times stamp.
-  bool PrefersLateDecoding() const;
-
  private:
   typedef std::map<uint8_t, VCMDecoderMapItem*> DecoderMap;
   typedef std::map<uint8_t, VCMExtDecoderMapItem*> ExternalDecoderMap;