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}

modules/video_coding/video_receiver.cc

@@ -208,9 +208,7 @@ int32_t VideoReceiver::Decode(uint16_t maxWaitTimeMs) {
                               clock_->TimeInMilliseconds());
 
   if (first_frame_received_()) {
-    RTC_LOG(LS_INFO) << "Received first "
-                     << (frame->Complete() ? "complete" : "incomplete")
-                     << " decodable video frame";
+    RTC_LOG(LS_INFO) << "Received first complete decodable video frame";
   }
 
   const int32_t ret = Decode(*frame);