Refactor X509Certificate caching to cache the OS handle, rather than the X509Certificate

net/base/x509_certificate_nss.cc

Index: net/base/x509_certificate_nss.cc
diff --git a/net/base/x509_certificate_nss.cc b/net/base/x509_certificate_nss.cc
index 9c634a8549a36f4217ad6919f3f51b42eeeb4f2c..db9f6a54163fef3571aafcc6bdf3ec3c1fdee467 100644
--- a/net/base/x509_certificate_nss.cc
+++ b/net/base/x509_certificate_nss.cc
@@ -750,8 +750,7 @@ X509Certificate* X509Certificate::CreateSelfSigned(
   // Save the signed result to the cert.
   cert->derCert = *result;
 
-  X509Certificate* x509_cert =
-      CreateFromHandle(cert, SOURCE_LONE_CERT_IMPORT, OSCertHandles());
+  X509Certificate* x509_cert = CreateFromHandle(cert, OSCertHandles());
   CERT_DestroyCertificate(cert);
   return x509_cert;
 }