Add device policy to disallow shutdown

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

+// 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.
+
+#include "chrome/browser/ui/webui/chromeos/login/shutdown_policy_observer.h"
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"

[bartfab (slow), 2014/12/08 16:49:45]

Nit: Not used.

[cschuet (SLOW), 2014/12/08 18:57:04]

Done.

+#include "chromeos/settings/cros_settings_names.h"
+#include "chromeos/settings/cros_settings_provider.h"
+
+namespace chromeos {
+
+ShutdownPolicyObserver::ShutdownPolicyObserver(CrosSettings* cros_settings,
+                                               Delegate* delegate)
+    : cros_settings_(cros_settings), delegate_(nullptr), weak_factory_(this) {
+  delegate_ = delegate;

[bartfab (slow), 2014/12/08 16:49:45]

Nit: Move this to the initialization one line above:

delegate_(delegate)

[cschuet (SLOW), 2014/12/08 18:57:04]

Done.

+  if (delegate_) {
+    shutdown_policy_subscription_ = cros_settings_->AddSettingsObserver(
+        kShutdownIsReboot,
+        base::Bind(&ShutdownPolicyObserver::OnShutdownPolicyChanged,
+                   weak_factory_.GetWeakPtr()));
+  } else {
+    shutdown_policy_subscription_.reset();

[bartfab (slow), 2014/12/08 16:49:45]

This is unnecessary. Since we are in the constructor, nobody can have created a
subscription yet.

[cschuet (SLOW), 2014/12/08 18:57:04]

Done.

+  }
+}
+
+ShutdownPolicyObserver::~ShutdownPolicyObserver() {
+}
+
+void ShutdownPolicyObserver::Shutdown() {
+  shutdown_policy_subscription_.reset();
+  delegate_ = nullptr;
+}
+
+void ShutdownPolicyObserver::OnShutdownPolicyChanged() {
+  CrosSettingsProvider::TrustedStatus status =
+      cros_settings_->PrepareTrustedValues(
+          base::Bind(&ShutdownPolicyObserver::OnShutdownPolicyChanged,
+                     weak_factory_.GetWeakPtr()));
+  if (status != CrosSettingsProvider::TRUSTED)
+    return;
+
+  // Get the updated policy.
+  bool shutdown_is_reboot = false;
+  cros_settings_->GetBoolean(kShutdownIsReboot, &shutdown_is_reboot);
+  if (delegate_)
+    delegate_->OnShutdownPolicyChanged(shutdown_is_reboot);
+}
+
+void ShutdownPolicyObserver::CheckIfShutdownIsReboot(

[bartfab (slow), 2014/12/08 16:49:45]

You can extract the logic shared by OnShutdownPolicyChanged() and
CheckIfShutdownIsReboot() into a helper method if you make the action to be
taken always be a callback (either a |ShutdownIsRebootCallback| passed in by the
user or a base::Bind() that informs he delegate).

[cschuet (SLOW), 2014/12/08 18:57:04]

Done.

+    const ShutdownIsRebootCallback& callback) {
+  CrosSettingsProvider::TrustedStatus status =
+      cros_settings_->PrepareTrustedValues(
+          base::Bind(&ShutdownPolicyObserver::CheckIfShutdownIsReboot,
+                     weak_factory_.GetWeakPtr(), callback));
+  if (status != CrosSettingsProvider::TRUSTED)
+    return;
+
+  // Get the updated policy.
+  bool shutdown_is_reboot = false;
+  cros_settings_->GetBoolean(kShutdownIsReboot, &shutdown_is_reboot);
+  callback.Run(shutdown_is_reboot);

[bartfab (slow), 2014/12/08 16:49:45]

Nit: #include "base/callback.h"

[cschuet (SLOW), 2014/12/08 18:57:04]

Done.

+}
+
+}  // namespace chromeos