Remove deprected functions from EncodedImageCallback and RtpRtcp

Removed EncodedImageCallback::Encoded() and RtpRtcp::SendOutgoingData().
These methods should no longer be used anywhere and it's safe to remove
them.

BUG=chromium:621691

Committed: https://crrev.com/c681250aaa2025836db7669694e323898e5c2ca7
Review-Url: https://codereview.webrtc.org/2405173006
Cr-Original-Commit-Position: refs/heads/master@{#14923}
Cr-Commit-Position: refs/heads/master@{#14935}
diff --git a/webrtc/modules/video_coding/video_receiver.cc b/webrtc/modules/video_coding/video_receiver.cc
index 8b61524..475f686 100644
--- a/webrtc/modules/video_coding/video_receiver.cc
+++ b/webrtc/modules/video_coding/video_receiver.cc
@@ -270,8 +270,8 @@
     if (qp_parser_.GetQp(*frame, &qp)) {
       encoded_image.qp_ = qp;
     }
-    pre_decode_image_callback_->Encoded(encoded_image, frame->CodecSpecific(),
-                                        nullptr);
+    pre_decode_image_callback_->OnEncodedImage(encoded_image,
+                                               frame->CodecSpecific(), nullptr);
   }
 
   rtc::CritScope cs(&receive_crit_);