Implement PermissionService::GetNextPermissionChange.

chrome/browser/permissions/permission_manager.h

 // Copyright 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_PERMISSIONS_PERMISSION_MANAGER_H_
 #define CHROME_BROWSER_PERMISSIONS_PERMISSION_MANAGER_H_
 
 #include "base/callback_forward.h"
+#include "base/id_map.h"
 #include "base/macros.h"
+#include "components/content_settings/core/browser/content_settings_observer.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "content/public/browser/permission_manager.h"
 
+
 class Profile;
 
 namespace content {
 enum class PermissionType;
 };  // namespace content
 
 class PermissionManager : public KeyedService,
-                          public content::PermissionManager {
+                          public content::PermissionManager,
+                          public content_settings::Observer {
  public:
   explicit PermissionManager(Profile* profile);
   ~PermissionManager() override;
 
   // content::PermissionManager implementation.
   void RequestPermission(
       content::PermissionType permission,
       content::WebContents* web_contents,
       int request_id,
       const GURL& requesting_origin,
       bool user_gesture,
       const base::Callback<void(content::PermissionStatus)>& callback) override;
   void CancelPermissionRequest(content::PermissionType permission,
                                content::WebContents* web_contents,
                                int request_id,
                                const GURL& requesting_origin) override;
   void ResetPermission(content::PermissionType permission,
                        const GURL& requesting_origin,
                        const GURL& embedding_origin) override;
   content::PermissionStatus GetPermissionStatus(
       content::PermissionType permission,
       const GURL& requesting_origin,
       const GURL& embedding_origin) override;
   void RegisterPermissionUsage(content::PermissionType permission,
                                const GURL& requesting_origin,
                                const GURL& embedding_origin) override;
+  int SubscribePermissionStatusChange(
+      content::PermissionType permission,
+      const GURL& requesting_origin,
+      const GURL& embedding_origin,
+      const base::Callback<void(content::PermissionStatus)>& callback) override;
+  void UnsubscribePermissionStatusChange(int subscription_id) override;
 
  private:
+  struct Subscription;
+  using SubscriptionsMap = IDMap<Subscription, IDMapOwnPointer>;
+
+  // content_settings::Observer implementation.
+  void OnContentSettingChanged(const ContentSettingsPattern& primary_pattern,
+                               const ContentSettingsPattern& secondary_pattern,
+                               ContentSettingsType content_type,
+                               std::string resource_identifier) override;
+
   Profile* profile_;
+  SubscriptionsMap subscriptions_;
 
   DISALLOW_COPY_AND_ASSIGN(PermissionManager);
 };
 
 #endif // CHROME_BROWSER_PERMISSIONS_PERMISSION_MANAGER_H_