Add DeviceDisablingManager to manage device disabling

chrome/browser/chromeos/system/device_disabling_manager.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_CHROMEOS_SYSTEM_DEVICE_DISABLING_MANAGER_H_
+#define CHROME_BROWSER_CHROMEOS_SYSTEM_DEVICE_DISABLING_MANAGER_H_
+
+#include <string>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+
+namespace policy {
+class BrowserPolicyConnectorChromeOS;
+}
+
+namespace chromeos {
+namespace system {
+
+// If an enrolled device is lost or stolen, it can be remotely disabled by its
+// owner. The disabling is triggered in two different ways, depending on the
+// state the device is in:
+// - If the device has been wiped, it will perform a hash dance during OOBE to
+//   find out whether any persistent state has been stored for it on the server.
+//   If so, persistent state is retrieved as a |DeviceStateRetrievalResponse|
+//   protobuf, parsed and written to the |prefs::kServerBackedDeviceState| local
+//   state pref. At the appropriate place in the OOBE flow, the
+//   |WizardController| will call CheckWhetherDeviceDisabledDuringOOBE() to find
+//   out whether the device is disabled, causing it to either show or skip the
+//   device disabled screen.
+// - If the device has not been wiped, the disabled state is retrieved with
+//   every device policy fetch as part of the |PolicyData| protobuf, parsed and
+//   written to the |chromeos::kDeviceDisabled| cros setting.
+//
+//   TODO(bartfab): Make this class subscribe to the cros setting and trigger
+//   the device disabled screen. http://crbug.com/425574
+class DeviceDisablingManager {
+ public:
+  using DeviceDisabledCheckCallback = base::Callback<void(bool)>;
+
+  explicit DeviceDisablingManager(
+      policy::BrowserPolicyConnectorChromeOS* browser_policy_connector);
+  ~DeviceDisablingManager();
+
+  // Returns the cached disabled message. The message is only guaranteed to be
+  // up to date if the disabled screen was triggered.
+  const std::string& disabled_message() const { return disabled_message_; }
+
+  // Checks whether the device is disabled. |callback| will be invoked with the
+  // result of the check.
+  void CheckWhetherDeviceDisabledDuringOOBE(
+      const DeviceDisabledCheckCallback& callback);
+
+ private:
+  policy::BrowserPolicyConnectorChromeOS* browser_policy_connector_;
+
+  // A cached copy of the message to show on the device disabled screen.
+  std::string disabled_message_;
+
+  base::WeakPtrFactory<DeviceDisablingManager> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(DeviceDisablingManager);
+};
+
+}  // namespace system
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_SYSTEM_DEVICE_DISABLING_MANAGER_H_