Fix VideoRtpDepacketizerVp{8,9} copy assignment signature.

Bug: none
Change-Id: I4adca8b4cbf4ffa15172fabc1eaba8c2b65c6fb1
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/222650
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Commit-Queue: Philip Eliasson <philipel@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34306}

modules/rtp_rtcp/source/video_rtp_depacketizer_vp8.h

diff --git a/modules/rtp_rtcp/source/video_rtp_depacketizer_vp8.h b/modules/rtp_rtcp/source/video_rtp_depacketizer_vp8.h
index a757399..3d7cb32 100644
--- a/modules/rtp_rtcp/source/video_rtp_depacketizer_vp8.h
+++ b/modules/rtp_rtcp/source/video_rtp_depacketizer_vp8.h
@@ -25,7 +25,7 @@
  public:
   VideoRtpDepacketizerVp8() = default;
   VideoRtpDepacketizerVp8(const VideoRtpDepacketizerVp8&) = delete;
-  VideoRtpDepacketizerVp8& operator=(VideoRtpDepacketizerVp8&) = delete;
+  VideoRtpDepacketizerVp8& operator=(const VideoRtpDepacketizerVp8&) = delete;
   ~VideoRtpDepacketizerVp8() override = default;
 
   // Parses vp8 rtp payload descriptor.

modules/rtp_rtcp/source/video_rtp_depacketizer_vp9.h

diff --git a/modules/rtp_rtcp/source/video_rtp_depacketizer_vp9.h b/modules/rtp_rtcp/source/video_rtp_depacketizer_vp9.h
index c622cbc..4bb358a 100644
--- a/modules/rtp_rtcp/source/video_rtp_depacketizer_vp9.h
+++ b/modules/rtp_rtcp/source/video_rtp_depacketizer_vp9.h
@@ -25,7 +25,7 @@
  public:
   VideoRtpDepacketizerVp9() = default;
   VideoRtpDepacketizerVp9(const VideoRtpDepacketizerVp9&) = delete;
-  VideoRtpDepacketizerVp9& operator=(VideoRtpDepacketizerVp9&) = delete;
+  VideoRtpDepacketizerVp9& operator=(const VideoRtpDepacketizerVp9&) = delete;
   ~VideoRtpDepacketizerVp9() override = default;
 
   // Parses vp9 rtp payload descriptor.