Add DeviceADPolicyManager to provide AD policy.

chrome/browser/chromeos/policy/device_ad_policy_manager.h

+// Copyright 2016 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_AD_POLICY_MANAGER_H_
+#define CHROME_BROWSER_CHROMEOS_POLICY_DEVICE_AD_POLICY_MANAGER_H_
+
+#include <memory>
+
+#include "components/policy/core/common/cloud/cloud_policy_store.h"
+#include "components/policy/core/common/configuration_policy_provider.h"
+
+namespace policy {
+
+// ConfigurationPolicyProvider for policy from Active Directory.  The policy is
+// fetched from the Domain Controller by authpolicyd which stores it in session
+// manager and from where it is loaded by DeviceADPolicyManager.
+// TODO(tnagel): Wire RefreshPolicies() through to authpolicyd.
+class DeviceADPolicyManager : public ConfigurationPolicyProvider,

[emaxx, 2016/11/11 15:25:08]

I understand that unabbreviated "AD" will be quite long, but I think that this
acronym will be unclear to most of the Chromium committers.
Also quoting the style guide:
The same concern applies to other parts of the CL that use this "ad" acronym.

[Thiemo Nagel, 2016/11/16 19:11:01]

I guess you're right.  I'm converting it all, please let me know if I've
overlooked it somewhere.

+                              public CloudPolicyStore::Observer {
+ public:
+  explicit DeviceADPolicyManager(std::unique_ptr<CloudPolicyStore> store);
+  ~DeviceADPolicyManager() override;
+
+  // ConfigurationPolicyProvider:
+  void Init(SchemaRegistry* registry) override;
+  void Shutdown() override;
+  bool IsInitializationComplete(PolicyDomain domain) const override;
+  void RefreshPolicies() override;
+
+  // CloudPolicyStore::Observer:
+  void OnStoreLoaded(CloudPolicyStore* cloud_policy_store) override;
+  void OnStoreError(CloudPolicyStore* cloud_policy_store) override;
+
+  const CloudPolicyStore* store() const { return store_.get(); }
+
+ private:
+  // Publishes the policy that's currently cached in the store.
+  void PublishPolicy();
+
+  std::unique_ptr<CloudPolicyStore> store_;
+};
+
+}  // namespace policy
+
+#endif  // CHROME_BROWSER_CHROMEOS_POLICY_DEVICE_AD_POLICY_MANAGER_H_