[Easy signin] Update the logic for getting user device list from cryptohome

chrome/browser/signin/easy_unlock_service_signin_chromeos.h

 // Copyright 2014 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_SIGNIN_EASY_UNLOCK_SERVICE_SIGNIN_CHROMEOS_H_
 #define CHROME_BROWSER_SIGNIN_EASY_UNLOCK_SERVICE_SIGNIN_CHROMEOS_H_
 
+#include <map>
 #include <string>
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
+#include "base/values.h"
 #include "chrome/browser/chromeos/login/easy_unlock/easy_unlock_types.h"
 #include "chrome/browser/signin/easy_unlock_service.h"
 
-namespace base {
-class DictionaryValue;
-class ListValue;
-}
-
 // EasyUnlockService instance that should be used for signin profile.
 class EasyUnlockServiceSignin : public EasyUnlockService {
  public:
   explicit EasyUnlockServiceSignin(Profile* profile);
   virtual ~EasyUnlockServiceSignin();
 
-  void SetAssociatedUser(const std::string& user_id);
+ private:
+  // The load state of a user's cryptohome key data.
+  enum UserDataState {
+    // Initial state, the key data is empty and not being loaded.
+    USER_DATA_STATE_INITIAL,
+    // The key data is empty, but being loaded.
+    USER_DATA_STATE_LOADING,
+    // The key data has been loaded.
+    USER_DATA_STATE_LOADED
+  };
 
- private:
+  // Structure containing a user's key data loaded from cryptohome.
+  struct UserData {
+    UserData();
+    ~UserData();
+
+    // The loading state of the data.
+    UserDataState state;
+
+    // The data as returned from cryptohome.
+    chromeos::EasyUnlockDeviceKeyDataList devices;
+
+    // The list of remote device dictionaries understood by Easy unlock app.
+    // This will be returned by |GetRemoteDevices| method.
+    base::ListValue remote_devices_value;
+
+   private:
+    DISALLOW_COPY_AND_ASSIGN(UserData);
+  };
+
   // EasyUnlockService implementation:
   virtual EasyUnlockService::Type GetType() const OVERRIDE;
   virtual std::string GetUserEmail() const OVERRIDE;
   virtual void LaunchSetup() OVERRIDE;
   virtual const base::DictionaryValue* GetPermitAccess() const OVERRIDE;
   virtual void SetPermitAccess(const base::DictionaryValue& permit) OVERRIDE;
   virtual void ClearPermitAccess() OVERRIDE;
   virtual const base::ListValue* GetRemoteDevices() const OVERRIDE;
   virtual void SetRemoteDevices(const base::ListValue& devices) OVERRIDE;
   virtual void ClearRemoteDevices() OVERRIDE;
   virtual void RunTurnOffFlow() OVERRIDE;
   virtual void ResetTurnOffFlow() OVERRIDE;
   virtual TurnOffFlowStatus GetTurnOffFlowStatus() const OVERRIDE;
   virtual std::string GetChallenge() const OVERRIDE;
   virtual bool IsAllowedInternal() OVERRIDE;
   virtual void InitializeInternal() OVERRIDE;
 
-  // Fetches |remote_devices_| info from cryptohome keys.
-  void FetchCryptohomeKeys();
+  // Loads the device data associated with the user's Easy unlock keys from
+  // crypthome.
+  void LoadCurrentUserDataIfNeeded();
 
-  // Callback invoked when the cryptohome keys are fetched.
-  void OnCryptohomeKeysFetched(
+  // Callback invoked when the user's device data is loaded from cryptohome.
+  void OnUserDataLoaded(
+      const std::string& user_id,
       bool success,
-      const chromeos::EasyUnlockDeviceKeyDataList& devices);
+      const chromeos::EasyUnlockDeviceKeyDataList& data);
 
-  // User id of the associated user.
+  // If the device data has been loaded for the current user, returns is.
+  // Otherwise, returns NULL.
+  const UserData* FindLoadedDataForCurrentUser() const;
+
+  // User id of the user currently associated with the service.
   std::string user_id_;
 
-  // Remote devices of the associated user.
-  chromeos::EasyUnlockDeviceKeyDataList remote_devices_;
-  scoped_ptr<base::ListValue> remote_devices_value_;
+  // Maps user ids to their fetched cryptohome key data.
+  std::map<std::string, UserData*> user_data_;
+
+  // Whether failed attempts to load user data should be retried.
+  // This is to handle case where cryptohome daemon is not started in time the
+  // service attempts to load some data. Retries will be allowed only until the
+  // first data load finishes (even if it fails).
+  bool allow_cryptohome_backoff_;
 
   base::WeakPtrFactory<EasyUnlockServiceSignin> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(EasyUnlockServiceSignin);
 };
 
 #endif  // CHROME_BROWSER_SIGNIN_EASY_UNLOCK_SERVICE_SIGNIN_CHROMEOS_H_