Add two UMA counters for IPv4 and IPv6 local candidates gathered in WebRTC PeerConnection.

content/renderer/media/rtc_peer_connection_handler.h

Index: content/renderer/media/rtc_peer_connection_handler.h
diff --git a/content/renderer/media/rtc_peer_connection_handler.h b/content/renderer/media/rtc_peer_connection_handler.h
index 2a440f1e439040009d5699d5c0d76ec723e45025..81be1ac59a54d25065fa163bfa9a2f7cf044fbc1 100644
--- a/content/renderer/media/rtc_peer_connection_handler.h
+++ b/content/renderer/media/rtc_peer_connection_handler.h
@@ -218,6 +218,10 @@ class CONTENT_EXPORT RTCPeerConnectionHandler
   // Counter for a UMA stat reported at destruction time.
   int num_data_channels_created_;
 
+  // Counter for number of IPv4 and IPv6 local candidates.
+  int num_local_candidates_ipv4_;
+  int num_local_candidates_ipv6_;
+
   // |native_peer_connection_| is the libjingle native PeerConnection object.
   scoped_refptr<webrtc::PeerConnectionInterface> native_peer_connection_;