Return a copy of the supported RTP header extensions instead of a reference.

talk/media/base/mediaengine.h

 /*
  * libjingle
  * Copyright 2004 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *  1. Redistributions of source code must retain the above copyright notice,
  *     this list of conditions and the following disclaimer.
  *  2. Redistributions in binary form must reproduce the above copyright notice,
@@ skipping 90 matching lines @@
   // Device configuration
   // Gets the current speaker volume, as a value between 0 and 255.
   virtual bool GetOutputVolume(int* level) = 0;
   // Sets the current speaker volume, as a value between 0 and 255.
   virtual bool SetOutputVolume(int level) = 0;
 
   // Gets the current microphone level, as a value between 0 and 10.
   virtual int GetInputLevel() = 0;
 
   virtual const std::vector<AudioCodec>& audio_codecs() = 0;
-  virtual const std::vector<RtpHeaderExtension>&
-      audio_rtp_header_extensions() = 0;
+  virtual std::vector<RtpHeaderExtension> audio_rtp_header_extensions() = 0;

[pthatcher1, 2015/12/01 18:40:46]

This is only called in one place (channelmanager.cc), so I think we should its
name as well, preferably to GetAudioCapabilities() and GetVideoCapabilities().

[stefan-webrtc, 2015/12/04 14:06:11]

Done.

   virtual const std::vector<VideoCodec>& video_codecs() = 0;
-  virtual const std::vector<RtpHeaderExtension>&
-      video_rtp_header_extensions() = 0;
+  virtual std::vector<RtpHeaderExtension> video_rtp_header_extensions() = 0;
 
   // Starts AEC dump using existing file.
   virtual bool StartAecDump(rtc::PlatformFile file) = 0;
 
   // Stops recording AEC dump.
   virtual void StopAecDump() = 0;
 
   // Starts RtcEventLog using existing file.
   virtual bool StartRtcEventLog(rtc::PlatformFile file) = 0;
 
@@ skipping 69 matching lines @@
   virtual bool SetOutputVolume(int level) {
     return voice_.SetOutputVolume(level);
   }
 
   virtual int GetInputLevel() {
     return voice_.GetInputLevel();
   }
   virtual const std::vector<AudioCodec>& audio_codecs() {
     return voice_.codecs();
   }
-  virtual const std::vector<RtpHeaderExtension>& audio_rtp_header_extensions() {
-    return voice_.rtp_header_extensions();
+  virtual std::vector<RtpHeaderExtension> audio_rtp_header_extensions() {
+    return voice_.SupportedRtpHeaderExtensions();
   }
   virtual const std::vector<VideoCodec>& video_codecs() {
     return video_.codecs();
   }
-  virtual const std::vector<RtpHeaderExtension>& video_rtp_header_extensions() {
-    return video_.rtp_header_extensions();
+  virtual std::vector<RtpHeaderExtension> video_rtp_header_extensions() {
+    return video_.SupportedRtpHeaderExtensions();
   }
 
   virtual bool StartAecDump(rtc::PlatformFile file) {
     return voice_.StartAecDump(file);
   }
 
   virtual void StopAecDump() {
     voice_.StopAecDump();
   }
 
@@ skipping 23 matching lines @@
   bool SetDevices(const Device* in_device, const Device* out_device) {
     return true;
   }
   bool GetOutputVolume(int* level) {
     *level = 0;
     return true;
   }
   bool SetOutputVolume(int level) { return true; }
   int GetInputLevel() { return 0; }
   const std::vector<AudioCodec>& codecs() { return codecs_; }
-  const std::vector<RtpHeaderExtension>& rtp_header_extensions() {
+  std::vector<RtpHeaderExtension> SupportedRtpHeaderExtensions() const {
     return rtp_header_extensions_;
   }
   bool StartAecDump(rtc::PlatformFile file) { return false; }
   bool StartRtcEventLog(rtc::PlatformFile file) { return false; }
   void StopRtcEventLog() {}
 
  private:
   std::vector<AudioCodec> codecs_;
   std::vector<RtpHeaderExtension> rtp_header_extensions_;
 };
 
 // NullVideoEngine can be used with CompositeMediaEngine in the case where only
 // a voice engine is desired.
 class NullVideoEngine {
  public:
   bool Init(rtc::Thread* worker_thread) { return true; }
   void Terminate() {}
   // If you need this to return an actual channel, use FakeMediaEngine instead.
   VideoMediaChannel* CreateChannel(
       const VideoOptions& options,
       VoiceMediaChannel* voice_media_channel) {
     return NULL;
   }
   bool SetOptions(const VideoOptions& options) { return true; }
   bool SetDefaultEncoderConfig(const VideoEncoderConfig& config) {
     return true;
   }
   const std::vector<VideoCodec>& codecs() { return codecs_; }
-  const std::vector<RtpHeaderExtension>& rtp_header_extensions() {
+  std::vector<RtpHeaderExtension> SupportedRtpHeaderExtensions() const {
     return rtp_header_extensions_;
   }
 
  private:
   std::vector<VideoCodec> codecs_;
   std::vector<RtpHeaderExtension> rtp_header_extensions_;
 };
 
 typedef CompositeMediaEngine<NullVoiceEngine, NullVideoEngine> NullMediaEngine;
 
 enum DataChannelType {
   DCT_NONE = 0,
   DCT_RTP = 1,
   DCT_SCTP = 2
 };
 
 class DataEngineInterface {
  public:
   virtual ~DataEngineInterface() {}
   virtual DataMediaChannel* CreateChannel(DataChannelType type) = 0;
   virtual const std::vector<DataCodec>& data_codecs() = 0;
 };
 
 }  // namespace cricket
 
 #endif  // TALK_MEDIA_BASE_MEDIAENGINE_H_