Remove manual implementaion of the c++17 insert_or_assign

In favor of the standard one
https://en.cppreference.com/w/cpp/container/map/insert_or_assign

Bug: None
Change-Id: I35e7a2fa11603caefca66e7caa3ecd1396601c98
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/247181
Auto-Submit: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Philip Eliasson <philipel@webrtc.org>
Commit-Queue: Philip Eliasson <philipel@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35711}
diff --git a/modules/remote_bitrate_estimator/remote_bitrate_estimator_abs_send_time.cc b/modules/remote_bitrate_estimator/remote_bitrate_estimator_abs_send_time.cc
index ae960ab..0bc4f6d 100644
--- a/modules/remote_bitrate_estimator/remote_bitrate_estimator_abs_send_time.cc
+++ b/modules/remote_bitrate_estimator/remote_bitrate_estimator_abs_send_time.cc
@@ -278,13 +278,7 @@
     TimeoutStreams(now);
     RTC_DCHECK(inter_arrival_);
     RTC_DCHECK(estimator_);
-    // TODO(danilchap): Replace 5 lines below with insert_or_assign when that
-    // c++17 function is available.
-    auto inserted = ssrcs_.insert(std::make_pair(ssrc, now));
-    if (!inserted.second) {
-      // Already inserted, update.
-      inserted.first->second = now;
-    }
+    ssrcs_.insert_or_assign(ssrc, now);
 
     // For now only try to detect probes while we don't have a valid estimate.
     // We currently assume that only packets larger than 200 bytes are paced by