Allow RtpPacket::SetPayloadSize to increase payload size

webrtc/modules/rtp_rtcp/source/rtp_packet.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_PACKET_H_
@@ skipping 78 matching lines @@
   template <typename Extension, typename... Values>
   bool GetExtension(Values...) const;
 
   template <typename Extension, typename... Values>
   bool SetExtension(Values...);
 
   template <typename Extension>
   bool ReserveExtension();
 
   // Reserve size_bytes for payload. Returns nullptr on failure.
+  uint8_t* SetPayloadSize(size_t size_bytes);
+  // Same as SetPayloadSize but doesn't guarantee to keep current payload.
   uint8_t* AllocatePayload(size_t size_bytes);
-  void SetPayloadSize(size_t size_bytes);
   bool SetPadding(uint8_t size_bytes, Random* random);
 
  protected:
   // |extensions| required for SetExtension/ReserveExtension functions during
   // packet creating and used if available in Parse function.
   // Adding and getting extensions will fail until |extensions| is
   // provided via constructor or IdentifyExtensions function.
   Packet();
   explicit Packet(const ExtensionManager* extensions);
   Packet(const Packet&) = default;
@@ skipping 75 matching lines @@
   uint16_t offset = 0;
   if (!AllocateExtension(Extension::kId, Extension::kValueSizeBytes, &offset))
     return false;
   memset(WriteAt(offset), 0, Extension::kValueSizeBytes);
   return true;
 }
 }  // namespace rtp
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_RTP_RTCP_SOURCE_RTP_PACKET_H_