Make X509Certificate::GetDEREncoded a static function taking an OSCertHandle

remoting/host/host_key_pair.cc

Index: remoting/host/host_key_pair.cc
diff --git a/remoting/host/host_key_pair.cc b/remoting/host/host_key_pair.cc
index 576bc1b0a5e3943d0e536de43d20a67443c09efb..4f81aa83a80563db34cfd02263d7448bf3e46d65 100644
--- a/remoting/host/host_key_pair.cc
+++ b/remoting/host/host_key_pair.cc
@@ -100,9 +100,11 @@ std::string HostKeyPair::GenerateCertificate() const {
           key_.get(), "CN=chromoting",
           base::RandInt(1, std::numeric_limits<int>::max()),
           base::TimeDelta::FromDays(1));
-  std::string result;
-  CHECK(cert->GetDEREncoded(&result));
-  return result;
+  std::string encoded;
+  bool result = net::X509Certificate::GetDEREncoded(cert->os_cert_handle(),
+                                                    &encoded);
+  CHECK(result);
+  return encoded;
 }
 
 }  // namespace remoting