To remove histogram WebRTC.PeerConnection.IceRegatheringReason expired
in M77, this CL removes the supporting codebase for it.
The removal of the histogram itself will be performed in crrev.com/c/5132272 .
This CL is a part of Chrome Code Health Rotation project.
Bug: chromium:1507997
Change-Id: I856e62920578e80970ca2453c86a588141bf120d
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/331880
Reviewed-by: Per Kjellander <perkj@webrtc.org>
Commit-Queue: Taiyo Mizuhashi <taiyo@chromium.org>
Cr-Commit-Position: refs/heads/main@{#41436}
b74a3e591f