Add a HostContentSettingsMap layer for Supervised Users.

chrome/browser/content_settings/content_settings_supervised_provider.h

Index: chrome/browser/content_settings/content_settings_supervised_provider.h
diff --git a/chrome/browser/content_settings/content_settings_supervised_provider.h b/chrome/browser/content_settings/content_settings_supervised_provider.h
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+++ b/chrome/browser/content_settings/content_settings_supervised_provider.h
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+// Copyright (c) 2015 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_CONTENT_SETTINGS_CONTENT_SETTINGS_SUPERVISED_PROVIDER_H_
+#define CHROME_BROWSER_CONTENT_SETTINGS_CONTENT_SETTINGS_SUPERVISED_PROVIDER_H_
+
+// A content setting provider that is set by the custodian of a supervised user.
+
+#include "base/synchronization/lock.h"
+#include "components/content_settings/core/browser/content_settings_binary_value_map.h"
+#include "components/content_settings/core/browser/content_settings_observable_provider.h"
+
+class PrefService;
+class SupervisedUserSettingsService;
+
+namespace content_settings {
+
+// SupervisedProvider that provides content-settings managed by the custodian
+// of a supervised user.
+class SupervisedProvider : public ObservableProvider {
+ public:
+  explicit SupervisedProvider(
+      SupervisedUserSettingsService* supervised_user_settings_service);
+  ~SupervisedProvider() override;
+
+  // ProviderInterface implementations.
+  RuleIterator* GetRuleIterator(ContentSettingsType content_type,
+                                const ResourceIdentifier& resource_identifier,
+                                bool incognito) const override;
+
+  bool SetWebsiteSetting(const ContentSettingsPattern& primary_pattern,
+                         const ContentSettingsPattern& secondary_pattern,
+                         ContentSettingsType content_type,
+                         const ResourceIdentifier& resource_identifier,
+                         base::Value* value) override;
+
+  void ClearAllContentSettingsRules(ContentSettingsType content_type) override;
+
+  void ShutdownOnUIThread() override;
+
+  // Callback on receiving settings from the supervised user settings service.
+  void OnSupervisedSettingsAvailable(const base::DictionaryValue* settings);
+
+ private:
+  BinaryValueMap value_map_;
+
+  // Used around accesses to the |value_map_| object to guarantee
+  // thread safety.
+  mutable base::Lock lock_;
+
+  base::WeakPtrFactory<SupervisedProvider> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(SupervisedProvider);
+};
+
+}  // namespace content_settings
+
+#endif  // CHROME_BROWSER_CONTENT_SETTINGS_CONTENT_SETTINGS_SUPERVISED_PROVIDER_H_