Fix chromium-style warnings.

webrtc/modules/rtp_rtcp/source/rtp_rtcp_defines_nullimpl.h

+/*
+ *  Copyright (c) 2016 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.
+ */
+
+#ifndef WEBRTC_MODULES_RTP_RTCP_SOURCE_RTP_RTCP_DEFINES_NULLIMPL_H_
+#define WEBRTC_MODULES_RTP_RTCP_SOURCE_RTP_RTCP_DEFINES_NULLIMPL_H_
+
+#include <stddef.h>
+
+#include "webrtc/modules/include/module_common_types.h"
+#include "webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h"
+
+namespace webrtc {
+
+// Null object version of RtpFeedback.
+class NullRtpFeedback : public RtpFeedback {
+ public:
+  ~NullRtpFeedback() override {}
+
+  int32_t OnInitializeDecoder(int8_t payload_type,
+                              const char payloadName[RTP_PAYLOAD_NAME_SIZE],
+                              int frequency,
+                              size_t channels,
+                              uint32_t rate) override;
+
+  void OnIncomingSSRCChanged(uint32_t ssrc) override {}
+  void OnIncomingCSRCChanged(uint32_t csrc, bool added) override {}
+};
+
+// Null object version of RtpData.
+class NullRtpData : public RtpData {
+ public:
+  ~NullRtpData() override {}
+
+  int32_t OnReceivedPayloadData(const uint8_t* payload_data,
+                                size_t payload_size,
+                                const WebRtcRTPHeader* rtp_header) override;
+
+  bool OnRecoveredPacket(const uint8_t* packet, size_t packet_length) override;
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_RTP_RTCP_SOURCE_RTP_RTCP_DEFINES_NULLIMPL_H_