Ability to persist RTCCertificate in IndexedDB (enables cloning).

content/renderer/media/rtc_certificate_generator.h

Index: content/renderer/media/rtc_certificate_generator.h
diff --git a/content/renderer/media/rtc_certificate_generator.h b/content/renderer/media/rtc_certificate_generator.h
index b582af9ea1a1d333b1596acfe07f1dfd486d94b8..3858db265cc947ca2fce961a908d64d4988702d8 100644
--- a/content/renderer/media/rtc_certificate_generator.h
+++ b/content/renderer/media/rtc_certificate_generator.h
@@ -34,6 +34,9 @@ class RTCCertificateGenerator : public blink::WebRTCCertificateGenerator {
       uint64_t expires_ms,
       std::unique_ptr<blink::WebRTCCertificateCallback> observer) override;
   bool isSupportedKeyParams(const blink::WebRTCKeyParams& key_params) override;
+  std::unique_ptr<blink::WebRTCCertificate> fromPEM(
+      const std::string& pem_private_key,
+      const std::string& pem_certificate) override;
 
  private:
   void generateCertificateWithOptionalExpiration(