Use stub impl when libcros fails to load

chrome/browser/chromeos/cros/login_library.h

 // Copyright (c) 2011 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 CHROME_BROWSER_CHROMEOS_CROS_LOGIN_LIBRARY_H_
 #define CHROME_BROWSER_CHROMEOS_CROS_LOGIN_LIBRARY_H_
 #pragma once
 
 #include <string>
 
 #include "base/memory/singleton.h"
 #include "third_party/cros/chromeos_login.h"
 
 namespace chromeos {
 
 // This interface defines the interaction with the ChromeOS login library APIs.
 class LoginLibrary {
  public:
   virtual ~LoginLibrary();
+
+  virtual void Init() = 0;
+
   // Requests that the Upstart signal login-prompt-ready be emitted.
   virtual void EmitLoginPromptReady() = 0;
 
   virtual void RequestRetrievePolicy(RetrievePolicyCallback callback,
                                      void* delegate_string) = 0;
 
   virtual void RequestStorePolicy(const std::string& policy,
                                   StorePolicyCallback callback,
                                   void* delegate_bool) = 0;
 
@@ skipping 17 matching lines @@
   virtual bool RestartJob(int pid, const std::string& command_line) = 0;
 
   // Factory function, creates a new instance and returns ownership.
   // For normal usage, access the singleton via CrosLibrary::Get().
   static LoginLibrary* GetImpl(bool stub);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_CROS_LOGIN_LIBRARY_H_