Delete unused copy constructors for VCMEncodedFrame and VCMFrameBuffer.

Bug: webrtc:9378
Change-Id: I742c7e2ca11f9c12d65add2bac9d7d19e09e3f14
Reviewed-on: https://webrtc-review.googlesource.com/85367
Reviewed-by: Rasmus Brandt <brandtr@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23744}

modules/video_coding/frame_buffer.cc

@@ -25,16 +25,6 @@ VCMFrameBuffer::VCMFrameBuffer()
 
 VCMFrameBuffer::~VCMFrameBuffer() {}
 
-VCMFrameBuffer::VCMFrameBuffer(const VCMFrameBuffer& rhs)
-    : VCMEncodedFrame(rhs),
-      _state(rhs._state),
-      _sessionInfo(),
-      _nackCount(rhs._nackCount),
-      _latestPacketTimeMs(rhs._latestPacketTimeMs) {
-  _sessionInfo = rhs._sessionInfo;
-  _sessionInfo.UpdateDataPointers(rhs._buffer, _buffer);
-}
-
 webrtc::FrameType VCMFrameBuffer::FrameType() const {
   return _sessionInfo.FrameType();
 }