settings: Add async system salt retrieval logic in DeviceOAuth2TokenServiceFactory

chrome/browser/chromeos/settings/device_oauth2_token_service_factory.h

 // Copyright 2013 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_SETTINGS_DEVICE_OAUTH2_TOKEN_SERVICE_FACTORY_H_
 #define CHROME_BROWSER_CHROMEOS_SETTINGS_DEVICE_OAUTH2_TOKEN_SERVICE_FACTORY_H_
 
+#include <queue>
+#include <string>
+
 #include "base/basictypes.h"
 #include "base/callback_forward.h"
+#include "base/memory/weak_ptr.h"
 
 namespace chromeos {
 
 class DeviceOAuth2TokenService;
 
 class DeviceOAuth2TokenServiceFactory {
  public:
   // Callback type used for Get() function.
   typedef base::Callback<void(DeviceOAuth2TokenService*)> GetCallback;
 
@@ skipping 18 matching lines @@
   // Called by ChromeBrowserMainPartsChromeOS in order to shutdown the
   // DeviceOAuth2TokenService instance and cancel all in-flight requests
   // before the required global data is destroyed (local state and request
   // context getter).
   static void Shutdown();
 
  private:
   DeviceOAuth2TokenServiceFactory();
   ~DeviceOAuth2TokenServiceFactory();
 
+  // Creates the token service asynchronously in the following steps:
+  // 1) Get the system salt from cryptohomed asynchronously
+  // 2) Create CryptohomeTokenEncryptor using the system salt
+  // 3) Create DeviceOAuth2TokenServiceFactory using the token encryptor
+  void CreateTokenService();
+
+  // Continuation of CreateTokenService(). Called when GetSystemSalt() is
+  // complete.
+  void DidGetSystemSalt(const std::string& system_salt);
+
+  // Runs the callback asynchronously. If |token_service_| is ready, the
+  // callback will be simply run via MessageLoop. Otherwise, the callback
+  // will be queued in |pending_callbacks_| and run when |token_service_| is
+  // ready.
+  void RunAsync(const GetCallback& callback);
+
+  // True if the factory is initialized (i.e. system salt retrieval is done
+  // regardless of whether it succeeded or failed).
+  bool initialized_;
   DeviceOAuth2TokenService* token_service_;
+  std::queue<GetCallback> pending_callbacks_;
+  base::WeakPtrFactory<DeviceOAuth2TokenServiceFactory> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DeviceOAuth2TokenServiceFactory);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_SETTINGS_DEVICE_OAUTH2_TOKEN_SERVICE_FACTORY_H_