Removes deprecated InsertPacket/TimeToSendPacket/TimeToSendPadding

The methods are no longer in use, this CL cleans away references and
updates any tests using them.

Bug: webrtc:10633
Change-Id: I2db301e0a021a2f85a8b9a74e409303baba407da
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/150520
Reviewed-by: Stefan Holmer <stefan@webrtc.org>
Reviewed-by: Sebastian Jansson <srte@webrtc.org>
Commit-Queue: Erik Språng <sprang@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28956}

modules/pacing/pacing_controller.cc

@@ -184,15 +184,6 @@ void PacingController::SetPacingRates(DataRate pacing_rate,
                       << " padding_budget_kbps=" << padding_rate.kbps();
 }
 
-void PacingController::InsertPacket(RtpPacketSender::Priority priority,
-                                    uint32_t ssrc,
-                                    uint16_t sequence_number,
-                                    int64_t capture_time_ms,
-                                    size_t bytes,
-                                    bool retransmission) {
-  RTC_NOTREACHED();
-}
-
 void PacingController::EnqueuePacket(std::unique_ptr<RtpPacketToSend> packet) {
   RTC_DCHECK(pacing_bitrate_ > DataRate::Zero())
       << "SetPacingRate must be called before InsertPacket.";