Modify UpdateLibrary to use async RequestUpdateCheck call

chrome/browser/chromeos/cros/update_library.h

 // Copyright (c) 2009 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_UPDATE_LIBRARY_H_
 #define CHROME_BROWSER_CHROMEOS_CROS_UPDATE_LIBRARY_H_
 #pragma once
 
 #include <string>
 
@@ skipping 44 matching lines @@
     virtual ~Observer() { }
     virtual void UpdateStatusChanged(UpdateLibrary* library) = 0;
   };
 
 //  static UpdateLibrary* GetStubImplementation();
 
   virtual ~UpdateLibrary() {}
   virtual void AddObserver(Observer* observer) = 0;
   virtual void RemoveObserver(Observer* observer) = 0;
 
-  // Initiates update check and returns true if check was initiated.
-  virtual bool CheckForUpdate() = 0;
+  // Requests an update check and calls |callback| when completed.
+  virtual void RequestUpdateCheck(chromeos::UpdateCallback callback,
+                                  void* user_data) = 0;
 
   // Reboots if update has been performed.
   virtual bool RebootAfterUpdate() = 0;
 
   // Sets the release track (channel). |track| should look like
   // "beta-channel" and "dev-channel". Returns true on success.
   virtual bool SetReleaseTrack(const std::string& track) = 0;
 
   // Returns the release track (channel). On error, returns an empty
   // string.
   virtual std::string GetReleaseTrack() = 0;
 
   virtual const Status& status() const = 0;
 
   // Factory function, creates a new instance and returns ownership.
   // For normal usage, access the singleton via CrosLibrary::Get().
   static UpdateLibrary* GetImpl(bool stub);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_CROS_UPDATE_LIBRARY_H_