Push API: Grace - allow one in ten pushes to show no notification.

content/public/browser/push_messaging_service.h

 // Copyright 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 CONTENT_PUBLIC_BROWSER_PUSH_MESSAGING_SERVICE_H_
 #define CONTENT_PUBLIC_BROWSER_PUSH_MESSAGING_SERVICE_H_
 
 #include <string>
 
 #include "base/callback.h"
 #include "content/common/content_export.h"
 #include "content/public/common/push_messaging_status.h"
 #include "third_party/WebKit/public/platform/WebPushPermissionStatus.h"
 #include "url/gurl.h"
 
 namespace content {
 
+class ServiceWorkerContext;
+
 // A push service-agnostic interface that the Push API uses for talking to
 // push messaging services like GCM. Must only be used on the UI thread.
 class CONTENT_EXPORT PushMessagingService {
  public:
+  using GetNotificationsShownCallback =
+      base::Callback<void(const std::string& notifications_shown,
+                          bool success, bool not_found)>;
+
+  using ResultCallback = base::Callback<void(bool success)>;
+
   using RegisterCallback =
       base::Callback<void(const std::string& /* registration_id */,
                           PushRegistrationStatus /* status */)>;
   using UnregisterCallback = base::Callback<void(PushUnregistrationStatus)>;
 
+  // Provide a storage mechanism to read/write an opaque
+  // "notifications_shown_by_last_few_pushes" string associated with a Service
+  // Worker registration. Stored data is deleted when the associated
+  // registration is deleted.
+  static void GetNotificationsShownByLastFewPushes(
+      ServiceWorkerContext* service_worker_context,
+      int64 service_worker_registration_id,
+      const GetNotificationsShownCallback& callback);
+  static void SetNotificationsShownByLastFewPushes(
+      ServiceWorkerContext* service_worker_context,
+      int64 service_worker_registration_id,
+      const GURL& origin,
+      const std::string& notifications_shown,
+      const ResultCallback& callback);
+
   virtual ~PushMessagingService() {}
 
   // Returns the absolute URL exposed by the push server where the webapp server
   // can send push messages. This is currently assumed to be the same for all
   // origins and push registrations.
   virtual GURL GetPushEndpoint() = 0;
 
   // Register the given |sender_id| with the push messaging service in a
   // document context. The frame is known and a permission UI may be displayed
   // to the user.
@@ skipping 23 matching lines @@
   // ever granted when the requesting origin matches the top level embedding
   // origin.
   virtual blink::WebPushPermissionStatus GetPermissionStatus(
       const GURL& requesting_origin,
       const GURL& embedding_origin) = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_PUSH_MESSAGING_SERVICE_H_