Refactor: Move RTCStatsCollector helper functions to anonymous namespace

webrtc/api/rtcstatscollector.h

Index: webrtc/api/rtcstatscollector.h
diff --git a/webrtc/api/rtcstatscollector.h b/webrtc/api/rtcstatscollector.h
index de374fc9a3096da53df2f1f1427f34361364148f..51d2705c2cb08ff5a8e74e0a7b3580f18958f93b 100644
--- a/webrtc/api/rtcstatscollector.h
+++ b/webrtc/api/rtcstatscollector.h
@@ -91,9 +91,6 @@ class RTCStatsCollector : public virtual rtc::RefCountInterface {
       int64_t timestamp_us,
       const std::map<std::string, CertificateStatsPair>& transport_cert_stats,
       RTCStatsReport* report) const;
-  void ProduceCertificateStatsFromSSLCertificateStats_s(
-      int64_t timestamp_us, const rtc::SSLCertificateStats& certificate_stats,
-      RTCStatsReport* report) const;
   // Produces |RTCDataChannelStats|.
   void ProduceDataChannelStats_s(
       int64_t timestamp_us, RTCStatsReport* report) const;
@@ -101,9 +98,6 @@ class RTCStatsCollector : public virtual rtc::RefCountInterface {
   void ProduceIceCandidateAndPairStats_s(
       int64_t timestamp_us, const SessionStats& session_stats,
       RTCStatsReport* report) const;
-  const std::string& ProduceIceCandidateStats_s(
-      int64_t timestamp_us, const cricket::Candidate& candidate, bool is_local,
-      RTCStatsReport* report) const;
   // Produces |RTCPeerConnectionStats|.
   void ProducePeerConnectionStats_s(
       int64_t timestamp_us, RTCStatsReport* report) const;