peerconnection: measure number of ice servers

for created and connected connections. This will allow making
an informed choice for
  https://webrtc-review.googlesource.com/c/src/+/234867

BUG=webrtc:13265

Change-Id: Ica3bb7695f53403e481ab1ea2a78fa2719fe44a2
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/234867
Reviewed-by: Johannes Kron <kron@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35203}
diff --git a/pc/peer_connection.cc b/pc/peer_connection.cc
index ad83a87..eb153eb 100644
--- a/pc/peer_connection.cc
+++ b/pc/peer_connection.cc
@@ -652,6 +652,10 @@
       },
       delay_ms);
 
+  // Record the number of configured ICE servers for all connections.
+  RTC_HISTOGRAM_COUNTS_LINEAR("WebRTC.PeerConnection.IceServers.Configured",
+                              configuration_.servers.size(), 0, 31, 32);
+
   return RTCError::OK();
 }
 
@@ -1896,6 +1900,10 @@
     }
     RTC_HISTOGRAM_ENUMERATION("WebRTC.PeerConnection.ProvisionalAnswer",
                               pranswer, kProvisionalAnswerMax);
+
+    // Record the number of configured ICE servers for connected connections.
+    RTC_HISTOGRAM_COUNTS_LINEAR("WebRTC.PeerConnection.IceServers.Connected",
+                                configuration_.servers.size(), 0, 31, 32);
   }
 }