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

talk/media/base/mediaengine.h

Index: talk/media/base/mediaengine.h
diff --git a/talk/media/base/mediaengine.h b/talk/media/base/mediaengine.h
index 3a6238a8d50142a22529b5b9f505388031d6cad2..440c79cca23d37fea44a9f2188c9765c45c2a5d9 100644
--- a/talk/media/base/mediaengine.h
+++ b/talk/media/base/mediaengine.h
@@ -108,11 +108,9 @@ class MediaEngineInterface {
   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;
@@ -202,14 +200,14 @@ class CompositeMediaEngine : public MediaEngineInterface {
   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) {
@@ -253,7 +251,7 @@ class NullVoiceEngine {
   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; }
@@ -282,7 +280,7 @@ class NullVideoEngine {
     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_;
   }