Removed unused _rotation_set variable from EncodedFrame.

Bug: none
Change-Id: I398417541fb66e58b0ad90c4b17c5d36eb61a004
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/154520
Reviewed-by: Niels Moller <nisse@webrtc.org>
Commit-Queue: Philip Eliasson <philipel@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29316}

modules/video_coding/encoded_frame.h

@@ -130,11 +130,6 @@ class VCMEncodedFrame : protected EncodedImage {
   bool _missingFrame;
   CodecSpecificInfo _codecSpecificInfo;
   webrtc::VideoCodecType _codec;
-
-  // Video rotation is only set along with the last packet for each frame
-  // (same as marker bit). This |_rotation_set| is only for debugging purpose
-  // to ensure we don't set it twice for a frame.
-  bool _rotation_set;
 };
 
 }  // namespace webrtc