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/include/video_coding.h

@@ -53,8 +53,7 @@ class VideoCodingModule : public Module {
   // Return value      : VCM_OK, on success.
   //                     < 0,    on error.
   virtual int32_t RegisterReceiveCodec(const VideoCodec* receiveCodec,
-                                       int32_t numberOfCores,
-                                       bool requireKeyFrame = false) = 0;
+                                       int32_t numberOfCores) = 0;
 
   // Register an external decoder object.
   //