Revert of Work on flexible mode and screen sharing.

webrtc/modules/video_coding/main/source/jitter_buffer.cc

Index: webrtc/modules/video_coding/main/source/jitter_buffer.cc
diff --git a/webrtc/modules/video_coding/main/source/jitter_buffer.cc b/webrtc/modules/video_coding/main/source/jitter_buffer.cc
index 23fb3f900412bd81ef156c0a317ccc5216a5edae..a5e774b0153d750bedbf194b058af307a37ae49e 100644
--- a/webrtc/modules/video_coding/main/source/jitter_buffer.cc
+++ b/webrtc/modules/video_coding/main/source/jitter_buffer.cc
@@ -686,6 +686,12 @@
 
   num_consecutive_old_packets_ = 0;
 
+  if (packet.codec == kVideoCodecVP9 &&
+      packet.codecSpecificHeader.codecHeader.VP9.flexible_mode) {
+    // TODO(asapersson): Add support for flexible mode.
+    return kGeneralError;
+  }
+
   VCMFrameBuffer* frame;
   FrameList* frame_list;
   const VCMFrameBufferEnum error = GetFrame(packet, &frame, &frame_list);