Add missing ifdefs to header files for SW video codecs.

Some functions were removed from the implementation files when this
flag is unset, but remained in the header files.

Bug: webrtc:7925
Change-Id: I9f8f969fb52f83c05ba02500a62dee78d1bcb0dc
Reviewed-on: https://webrtc-review.googlesource.com/80260
Reviewed-by: Magnus Jedvert <magjed@webrtc.org>
Reviewed-by: Steve Anton <steveanton@webrtc.org>
Reviewed-by: Taylor (left Google) <deadbeef@webrtc.org>
Commit-Queue: Steve Anton <steveanton@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24366}
diff --git a/api/peerconnectioninterface.h b/api/peerconnectioninterface.h
index 0fc2a2b..593084e 100644
--- a/api/peerconnectioninterface.h
+++ b/api/peerconnectioninterface.h
@@ -1327,6 +1327,7 @@
   ~PeerConnectionFactoryInterface() override = default;
 };
 
+#if defined(USE_BUILTIN_SW_CODECS)
 // Create a new instance of PeerConnectionFactoryInterface.
 //
 // This method relies on the thread it's called on as the "signaling thread"
@@ -1403,6 +1404,7 @@
     std::unique_ptr<FecControllerFactoryInterface> fec_controller_factory,
     std::unique_ptr<NetworkControllerFactoryInterface>
         network_controller_factory = nullptr);
+#endif
 
 // Create a new instance of PeerConnectionFactoryInterface with optional video
 // codec factories. These video factories represents all video codecs, i.e. no
@@ -1421,6 +1423,7 @@
     rtc::scoped_refptr<AudioMixer> audio_mixer,
     rtc::scoped_refptr<AudioProcessing> audio_processing);
 
+#if defined(USE_BUILTIN_SW_CODECS)
 // Create a new instance of PeerConnectionFactoryInterface with external audio
 // mixer.
 //
@@ -1453,6 +1456,7 @@
       default_adm, audio_encoder_factory, audio_decoder_factory,
       video_encoder_factory, video_decoder_factory);
 }
+#endif
 
 // This is a lower-level version of the CreatePeerConnectionFactory functions
 // above. It's implemented in the "peerconnection" build target, whereas the