Revert of Stop caching supported codecs in WebRtcVideoEngine2

webrtc/media/engine/webrtcvideoengine2.h

Index: webrtc/media/engine/webrtcvideoengine2.h
diff --git a/webrtc/media/engine/webrtcvideoengine2.h b/webrtc/media/engine/webrtcvideoengine2.h
index 1032e9c7e035bc4e5a0644d8d048d31d2edc469f..ef893d2e98fa2ee1ae60d45cd41b02277ac8b9ea 100644
--- a/webrtc/media/engine/webrtcvideoengine2.h
+++ b/webrtc/media/engine/webrtcvideoengine2.h
@@ -105,7 +105,7 @@
                                      const MediaConfig& config,
                                      const VideoOptions& options);
 
-  const std::vector<VideoCodec> codecs() const;
+  const std::vector<VideoCodec>& codecs() const;
   RtpCapabilities GetCapabilities() const;
 
   // Set a WebRtcVideoDecoderFactory for external decoding. Video engine does
@@ -119,6 +119,8 @@
       WebRtcVideoEncoderFactory* encoder_factory);
 
  private:
+  std::vector<VideoCodec> video_codecs_;
+
   bool initialized_;
 
   WebRtcVideoDecoderFactory* external_decoder_factory_;