Refactor certificate stats collection, added SSLCertificateStats.

webrtc/api/statscollector.h

Index: webrtc/api/statscollector.h
diff --git a/webrtc/api/statscollector.h b/webrtc/api/statscollector.h
index 8c359e48c45ef2416e9698db7c743b6a58da2e64..adbac44b8047b2c67f1351b16292c656f39976b6 100644
--- a/webrtc/api/statscollector.h
+++ b/webrtc/api/statscollector.h
@@ -91,17 +91,13 @@ class StatsCollector {
 
   bool CopySelectedReports(const std::string& selector, StatsReports* reports);
 
-  // Helper method for AddCertificateReports.
-  StatsReport* AddOneCertificateReport(
-      const rtc::SSLCertificate* cert, const StatsReport* issuer);
-
   // Helper method for creating IceCandidate report. |is_local| indicates
   // whether this candidate is local or remote.
   StatsReport* AddCandidateReport(const cricket::Candidate& candidate,
                                   bool local);
 
   // Adds a report for this certificate and every certificate in its chain, and
-  // returns the leaf certificate's report.
+  // returns the leaf certificate's report (|cert|'s report).
   StatsReport* AddCertificateReports(const rtc::SSLCertificate* cert);
 
   StatsReport* AddConnectionInfoReport(const std::string& content_name,