content: Cleanup class/struct forward declarations

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 <stdint.h>
 #include <string>
 #include <vector>
 
 #include "base/callback_forward.h"
 #include "content/common/content_export.h"
 #include "content/public/common/push_messaging_status.h"
 #include "third_party/WebKit/public/platform/modules/push_messaging/WebPushPermissionStatus.h"
 #include "url/gurl.h"
 
 namespace content {
 
 class BrowserContext;
-class ServiceWorkerContext;
 struct PushSubscriptionOptions;
 
 // 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 RegisterCallback =
       base::Callback<void(const std::string& registration_id,
                           const std::vector<uint8_t>& p256dh,
                           const std::vector<uint8_t>& auth,
@@ skipping 83 matching lines @@
       const GURL& origin,
       int64_t service_worker_registration_id,
       const std::string& subscription_id,
       const std::string& sender_id,
       const base::Closure& callback);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_PUSH_MESSAGING_SERVICE_H_