FEC protect H264 delta frames as well.

webrtc/modules/rtp_rtcp/source/rtp_format_h264.cc

 /*
  *  Copyright (c) 2014 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 314 matching lines @@
     *bytes_to_send = packet.size + kFuAHeaderSize;
     memcpy(buffer + kFuAHeaderSize, &payload_data_[packet.offset], packet.size);
   } else {
     *bytes_to_send = packet.size + kFuAHeaderSize;
     memcpy(buffer + kFuAHeaderSize, &payload_data_[packet.offset], packet.size);
   }
   packets_.pop();
 }
 
 ProtectionType RtpPacketizerH264::GetProtectionType() {
-  return (frame_type_ == kVideoFrameKey) ? kProtectedPacket
-                                         : kUnprotectedPacket;
+  return kProtectedPacket;
 }
 
 StorageType RtpPacketizerH264::GetStorageType(
     uint32_t retransmission_settings) {
   return kAllowRetransmission;
 }
 
 std::string RtpPacketizerH264::ToString() {
   return "RtpPacketizerH264";
 }
@@ skipping 20 matching lines @@
     // will depacketize the STAP-A into NAL units later.
     if (!ParseSingleNalu(parsed_payload, payload_data, payload_data_length))
       return false;
   }
 
   parsed_payload->payload = payload_data + offset;
   parsed_payload->payload_length = payload_data_length - offset;
   return true;
 }
 }  // namespace webrtc