Enable -Winconsistent-missing-override flag.

webrtc/modules/rtp_rtcp/source/rtp_payload_registry.cc

 /*
  *  Copyright (c) 2013 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 397 matching lines @@
     payload->name[RTP_PAYLOAD_NAME_SIZE - 1] = 0;
     strncpy(payload->name, payloadName, RTP_PAYLOAD_NAME_SIZE - 1);
     assert(frequency >= 1000);
     payload->typeSpecific.Audio.frequency = frequency;
     payload->typeSpecific.Audio.channels = channels;
     payload->typeSpecific.Audio.rate = rate;
     payload->audio = true;
     return payload;
   }
 
-  int GetPayloadTypeFrequency(const RtpUtility::Payload& payload) const {
+  int GetPayloadTypeFrequency(
+      const RtpUtility::Payload& payload) const override {
     return payload.typeSpecific.Audio.frequency;
   }
 };
 
 class RTPPayloadVideoStrategy : public RTPPayloadStrategy {
  public:
   bool CodecsMustBeUnique() const override { return false; }
 
   bool PayloadIsCompatible(const RtpUtility::Payload& payload,
                            const uint32_t frequency,
@@ skipping 29 matching lines @@
     }
     RtpUtility::Payload* payload = new RtpUtility::Payload;
 
     payload->name[RTP_PAYLOAD_NAME_SIZE - 1] = 0;
     strncpy(payload->name, payloadName, RTP_PAYLOAD_NAME_SIZE - 1);
     payload->typeSpecific.Video.videoCodecType = videoType;
     payload->audio = false;
     return payload;
   }
 
-  int GetPayloadTypeFrequency(const RtpUtility::Payload& payload) const {
+  int GetPayloadTypeFrequency(
+      const RtpUtility::Payload& payload) const override {
     return kVideoPayloadTypeFrequency;
   }
 };
 
 RTPPayloadStrategy* RTPPayloadStrategy::CreateStrategy(
     const bool handling_audio) {
   if (handling_audio) {
     return new RTPPayloadAudioStrategy();
   } else {
     return new RTPPayloadVideoStrategy();
   }
 }
 
 }  // namespace webrtc