Add device policy to disallow shutdown

chrome/browser/ui/webui/chromeos/login/shutdown_policy_observer.h

+// Copyright (c) 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_UI_WEBUI_CHROMEOS_LOGIN_SHUTDOWN_POLICY_OBSERVER_H_
+#define CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_SHUTDOWN_POLICY_OBSERVER_H_
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "chrome/browser/chromeos/settings/cros_settings.h"
+
+namespace chromeos {
+
+// This class observes the device setting "DeviceShutdownAllowed". Changes to
+// this policy are communicated to the ShutdownPolicyObserver::Delegate by
+// calling its OnShutdownPolicyChanged method with the new state of the policy.
+class ShutdownPolicyObserver {
+ public:
+  using ShutdownAllowedCallback = base::Callback<void(bool)>;
+
+  // This delegate is called when the "DeviceShutdownAllowed" policy changes.
+  class Delegate {
+   public:
+    virtual void OnShutdownPolicyChanged(bool shutdown_allowed) = 0;
+   protected:
+    virtual ~Delegate() {}
+  };
+
+  ShutdownPolicyObserver(CrosSettings* cros_settings, Delegate* delegate);
+  ~ShutdownPolicyObserver();
+
+  void CheckIfShutdownAllowed(const ShutdownAllowedCallback& callback);
+
+  // Resets the policy subscription and clears the delegate.
+  void Shutdown();
+ private:
+  void OnShutdownPolicyChanged();
+
+  CrosSettings* cros_settings_;
+
+  Delegate* delegate_;
+
+  scoped_ptr<CrosSettings::ObserverSubscription> shutdown_policy_subscription_;
+
+  base::WeakPtrFactory<ShutdownPolicyObserver> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(ShutdownPolicyObserver);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_SHUTDOWN_POLICY_OBSERVER_H_