Cache force-installed apps/extensions in device-local accounts

chrome/browser/chromeos/policy/device_local_account.h

 // Copyright (c) 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_POLICY_DEVICE_LOCAL_ACCOUNT_H_
 #define CHROME_BROWSER_CHROMEOS_POLICY_DEVICE_LOCAL_ACCOUNT_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 14 matching lines @@
     // Sentinel, must be last.
     TYPE_COUNT
   };
 
   DeviceLocalAccount(Type type,
                      const std::string& account_id,
                      const std::string& kiosk_app_id);
   ~DeviceLocalAccount();
 
   Type type;
+  // A device-local account has two identifiers:
+  // * The |account_id| is chosen by the entity that defines the device-local
+  //   account. The only constraints are that the |account_id| be unique and,
+  //   for legacy reasons, it contain an @ symbol.
+  // * The |user_id| is a synthesized identifier that is guaranteed to be
+  //   unique, contain an @ symbol, not collide with the |user_id| of any other
+  //   user on the device (such as regular users or supervised users) and be
+  //   identifiable as belonging to a device-local account by.
+  // The |account_id| is primarily used by policy code: If device policy defines
+  // a device-local account with a certain |account_id|, the user policy for
+  // that account has to be fetched by referencing the same |account_id|.
+  // The |user_id| is passed to the chromeos::UserManager where it becomes part
+  // of the global user list on the device. The |account_id| would not be safe
+  // to use here as it is a free-form identifier that could conflict with
+  // another |user_id| on the device and cannot be easily identified as
+  // belonging to a device-local account.
   std::string account_id;
   std::string user_id;
   std::string kiosk_app_id;
 };
 
 std::string GenerateDeviceLocalAccountUserId(const std::string& account_id,
                                              DeviceLocalAccount::Type type);
 
 // Determines whether |user_id| belongs to a device-local account and if so,
 // returns the type of device-local account in |type| unless |type| is NULL.
 bool IsDeviceLocalAccountUser(const std::string& user_id,
                               DeviceLocalAccount::Type* type);
 
 // Stores a list of device-local accounts in |cros_settings|. The accounts are
 // stored as a list of dictionaries with each dictionary containing the
 // information about one |DeviceLocalAccount|.
 void SetDeviceLocalAccounts(
     chromeos::CrosSettings* cros_settings,
     const std::vector<DeviceLocalAccount>& accounts);
 
 // Retrieves a list of device-local accounts from |cros_settings|.
 std::vector<DeviceLocalAccount> GetDeviceLocalAccounts(
     chromeos::CrosSettings* cros_settings);
 
 }  // namespace policy
 
 #endif  // CHROME_BROWSER_CHROMEOS_POLICY_DEVICE_LOCAL_ACCOUNT_H_