Removed _completeFrame since we never allow incomplete frames.

In the old jitter buffer the two VCMVideoProtection modes |kProtectionNone| and |kProtectionFEC| could be set on the jitter buffer for it to not wait for NACK and instead generate incomplete frames. This has not been possible for a long time.

Bug: webrtc:9378, webrtc:7408
Change-Id: I0a2d3ec34d721126c1128306d5fad88314f8d59f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/190680
Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
Reviewed-by: Sami Kalliomäki <sakal@webrtc.org>
Reviewed-by: Niels Moller <nisse@webrtc.org>
Commit-Queue: Philip Eliasson <philipel@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32513}
diff --git a/modules/video_coding/jitter_buffer.cc b/modules/video_coding/jitter_buffer.cc
index 9d2d3a2..772098a 100644
--- a/modules/video_coding/jitter_buffer.cc
+++ b/modules/video_coding/jitter_buffer.cc
@@ -298,8 +298,7 @@
   last_decoded_state_.SetState(frame);
   DropPacketsFromNackList(last_decoded_state_.sequence_num());
 
-  if ((*frame).IsSessionComplete())
-    UpdateAveragePacketsPerFrame(frame->NumPackets());
+  UpdateAveragePacketsPerFrame(frame->NumPackets());
 
   return frame;
 }