Revert of Add content type information to encoded images and corresponding rtp extension header

webrtc/modules/rtp_rtcp/source/rtp_header_extension.cc

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 21 matching lines @@
   return {Extension::kId, Extension::kValueSizeBytes, Extension::kUri};
 }
 
 constexpr ExtensionInfo kExtensions[] = {
     CreateExtensionInfo<TransmissionOffset>(),
     CreateExtensionInfo<AudioLevel>(),
     CreateExtensionInfo<AbsoluteSendTime>(),
     CreateExtensionInfo<VideoOrientation>(),
     CreateExtensionInfo<TransportSequenceNumber>(),
     CreateExtensionInfo<PlayoutDelayLimits>(),
-    CreateExtensionInfo<VideoContentTypeExtension>(),
 };
 
 // Because of kRtpExtensionNone, NumberOfExtension is 1 bigger than the actual
 // number of known extensions.
 static_assert(arraysize(kExtensions) ==
                   static_cast<int>(kRtpExtensionNumberOfExtensions) - 1,
               "kExtensions expect to list all known extensions");
 
 size_t ValueSize(RTPExtensionType type) {
   for (const ExtensionInfo& extension : kExtensions)
@@ skipping 90 matching lines @@
   }
   RTC_DCHECK(!IsRegistered(type));
 
   types_[id] = type;
   ids_[type] = id;
   total_values_size_bytes_ += (value_size + 1);
   return true;
 }
 
 }  // namespace webrtc