Delete unused argument |require_key_frame|

Bug: webrtc:7408
Change-Id: I59e73e6c54de5b2d293b83d54556e3d3fc6180f4
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/181073
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Reviewed-by: Philip Eliasson <philipel@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31884}

modules/video_coding/video_coding_impl.h

@@ -61,8 +61,7 @@ class VideoReceiver : public Module {
   ~VideoReceiver() override;
 
   int32_t RegisterReceiveCodec(const VideoCodec* receiveCodec,
-                               int32_t numberOfCores,
-                               bool requireKeyFrame);
+                               int32_t numberOfCores);
 
   void RegisterExternalDecoder(VideoDecoder* externalDecoder,
                                uint8_t payloadType);