Delete method EncodedFrame::GetBitstream, part 1

Only caller was the RtpFrameObject constructor, so it's
not needed in the interface.

To be able to delete downstream overrides, add a temporary
default implementation. Method will be completely deleted in part 2.

Bug: webrtc:9378
Change-Id: I9083b6284313b6ebce854c6f2cec4617953331d9
Reviewed-on: https://webrtc-review.googlesource.com/c/112128
Reviewed-by: Sebastian Jansson <srte@webrtc.org>
Reviewed-by: Åsa Persson <asapersson@webrtc.org>
Reviewed-by: Philip Eliasson <philipel@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25822}
diff --git a/modules/video_coding/frame_object.cc b/modules/video_coding/frame_object.cc
index 0172c55..f0c7449 100644
--- a/modules/video_coding/frame_object.cc
+++ b/modules/video_coding/frame_object.cc
@@ -49,7 +49,7 @@
   SetPlayoutDelay(first_packet->video_header.playout_delay);
 
   AllocateBitstreamBuffer(frame_size);
-  bool bitstream_copied = GetBitstream(_buffer);
+  bool bitstream_copied = packet_buffer_->GetBitstream(*this, _buffer);
   RTC_DCHECK(bitstream_copied);
   _encodedWidth = first_packet->width;
   _encodedHeight = first_packet->height;
@@ -122,15 +122,6 @@
   return codec_type_;
 }
 
-void RtpFrameObject::SetBitstream(rtc::ArrayView<const uint8_t> bitstream) {
-  AllocateBitstreamBuffer(bitstream.size());
-  memcpy(_buffer, bitstream.data(), _length);
-}
-
-bool RtpFrameObject::GetBitstream(uint8_t* destination) const {
-  return packet_buffer_->GetBitstream(*this, destination);
-}
-
 int64_t RtpFrameObject::ReceivedTime() const {
   return received_time_;
 }