Let VideoEncoderSoftwareFallbackWrapper own the wrapped encoder

webrtc/media/engine/webrtcvideoengine.cc

Index: webrtc/media/engine/webrtcvideoengine.cc
diff --git a/webrtc/media/engine/webrtcvideoengine.cc b/webrtc/media/engine/webrtcvideoengine.cc
index 9c11bb946930a5b5f09a48c4a65c617fc302702d..274b801625d7730930aaef47bfa1154e14f04090 100644
--- a/webrtc/media/engine/webrtcvideoengine.cc
+++ b/webrtc/media/engine/webrtcvideoengine.cc
@@ -1415,16 +1415,15 @@ WebRtcVideoChannel::WebRtcVideoSendStream::VideoSendStreamParameters::
 
 WebRtcVideoChannel::WebRtcVideoSendStream::AllocatedEncoder::AllocatedEncoder(
     std::unique_ptr<webrtc::VideoEncoder> encoder,
-    std::unique_ptr<webrtc::VideoEncoder> external_encoder,
+    bool is_external,
     const cricket::VideoCodec& codec,
     bool has_internal_source)
     : encoder_(std::move(encoder)),
-      external_encoder_(std::move(external_encoder)),
+      is_external_(is_external),
       codec_(codec),
       has_internal_source_(has_internal_source) {}
 
 void WebRtcVideoChannel::WebRtcVideoSendStream::AllocatedEncoder::Reset() {
-  external_encoder_.reset();
   encoder_.reset();
   codec_ = cricket::VideoCodec();
 }
@@ -1602,13 +1601,13 @@ WebRtcVideoChannel::WebRtcVideoSendStream::CreateVideoEncoder(
     if (external_encoder) {
       std::unique_ptr<webrtc::VideoEncoder> internal_encoder(
           new webrtc::VideoEncoderSoftwareFallbackWrapper(
-              codec, external_encoder.get()));
+              codec, std::move(external_encoder)));

[andersc, 2017/08/29 07:27:33]

Is it normal to call std::move both here and in the initializer list in
videoencodersoftwarefallbackwrapper.cc? If there is no harm I think it makes it
more readable, but I don't understand exactly what std::move does.

[magjed_webrtc, 2017/08/29 07:56:48]

Yes, it won't compile otherwise. Every time you create std::unique_ptr a from
another std::unique_ptr you need to call std::move, (it makes it a
std::unique_ptr&&). I move it twice actually, once here when moving it into the
argument of the VideoEncoderSoftwareFallbackWrapper ctor, and once when the ctor
moves it into its member variable.

       const webrtc::VideoCodecType codec_type =
           webrtc::PayloadStringToCodecType(codec.name);
       const bool has_internal_source =
           external_encoder_factory_->EncoderTypeHasInternalSource(codec_type);
       return AllocatedEncoder(std::move(internal_encoder),
-                              std::move(external_encoder), codec,
+                              true /* is_external */, codec,
                               has_internal_source);
     }
   }
@@ -1629,7 +1628,7 @@ WebRtcVideoChannel::WebRtcVideoSendStream::CreateVideoEncoder(
           internal_encoder_factory_->CreateVideoEncoder(codec));
     }
     return AllocatedEncoder(std::move(internal_encoder),
-                            nullptr /* external_encoder */, codec,
+                            false /* is_external */, codec,
                             false /* has_internal_source */);
   }