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/encoded_frame.h

@@ -92,10 +92,6 @@ class RTC_EXPORT VCMEncodedFrame : protected EncodedImage {
    */
   EncodedImage::Timing video_timing() const { return timing_; }
   EncodedImage::Timing* video_timing_mutable() { return &timing_; }
-  /**
-   *   True if this frame is complete, false otherwise
-   */
-  bool Complete() const { return _completeFrame; }
   /**
    *   True if there's a frame missing before this frame
    */