Polishing code to handle certificate generation failure in .mm files.

webrtc/sdk/objc/Framework/Classes/RTCConfiguration.mm

Index: webrtc/sdk/objc/Framework/Classes/RTCConfiguration.mm
diff --git a/webrtc/sdk/objc/Framework/Classes/RTCConfiguration.mm b/webrtc/sdk/objc/Framework/Classes/RTCConfiguration.mm
index 5beae99ed990a9ada498b6d069612842034902d3..0a63f69fd9819efb4cd1945c63b290e8eaa057a1 100644
--- a/webrtc/sdk/objc/Framework/Classes/RTCConfiguration.mm
+++ b/webrtc/sdk/objc/Framework/Classes/RTCConfiguration.mm
@@ -75,7 +75,8 @@
 
 #pragma mark - Private
 
-- (webrtc::PeerConnectionInterface::RTCConfiguration*)nativeConfiguration {
+- (webrtc::PeerConnectionInterface::RTCConfiguration *)
+    createNativeConfiguration {
   std::unique_ptr<webrtc::PeerConnectionInterface::RTCConfiguration>
       nativeConfig(new webrtc::PeerConnectionInterface::RTCConfiguration());
 
@@ -105,7 +106,7 @@
         rtc::RTCCertificateGenerator::GenerateCertificate(
             rtc::KeyParams(keyType), rtc::Optional<uint64_t>());
     if (!certificate) {
-      RTCLogWarning(@"Failed to generate certificate.");
+      RTCLogError(@"Failed to generate certificate.");
       return nullptr;
     }
     nativeConfig->certificates.push_back(certificate);