Handle certificate generation errors in chromoting host.

remoting/host/host_key_pair.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef REMOTING_HOST_HOST_KEY_PAIR_H_
 #define REMOTING_HOST_HOST_KEY_PAIR_H_
 
 #include <string>
 
 #include "base/memory/ref_counted.h"
@@ skipping 19 matching lines @@
   void Save(MutableHostConfig* host_config);
 
   crypto::RSAPrivateKey* private_key() { return key_.get(); }
 
   std::string GetAsString() const;
   std::string GetPublicKey() const;
   std::string GetSignature(const std::string& message) const;
 
   // Make a new copy of private key. Caller will own the generated private key.
   crypto::RSAPrivateKey* CopyPrivateKey() const;
+
+  // Generates self-signed certificate using the key pair. Returns empty string
+  // if cert generation fails (e.g. it may happen when the system clock is off).
   std::string GenerateCertificate() const;
 
  private:
   scoped_ptr<crypto::RSAPrivateKey> key_;
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_HOST_HOST_KEY_PAIR_H_