content: Cleanup class/struct forward declarations

content/browser/bluetooth/bluetooth_allowed_devices_map.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 CONTENT_BROWSER_BLUETOOTH_BLUETOOTH_ALLOWED_DEVICES_MAP_H_
 #define CONTENT_BROWSER_BLUETOOTH_BLUETOOTH_ALLOWED_DEVICES_MAP_H_
 
 #include <memory>
 #include <string>
 #include <unordered_map>
 #include <unordered_set>
 #include <vector>
 
 #include "base/optional.h"
 #include "content/common/bluetooth/web_bluetooth_device_id.h"
 #include "content/common/content_export.h"
 #include "third_party/WebKit/public/platform/modules/bluetooth/web_bluetooth.mojom.h"
 #include "url/origin.h"
 
 namespace device {
 class BluetoothUUID;
 }
 
 namespace content {
 
-struct BluetoothScanFilter;
-
 // Keeps track of which origins are allowed to access which devices and
 // their services.
 //
 // |AddDevice| generates device ids, which are random strings that are unique
 // in the map.
 class CONTENT_EXPORT BluetoothAllowedDevicesMap final {
  public:
   BluetoothAllowedDevicesMap();
   ~BluetoothAllowedDevicesMap();
 
@@ skipping 61 matching lines @@
       origin_to_device_id_to_services_map_;
 
   // Keep track of all device_ids in the map.
   std::unordered_set<WebBluetoothDeviceId, WebBluetoothDeviceIdHash>
       device_id_set_;
 };
 
 }  //  namespace content
 
 #endif  // CONTENT_BROWSER_BLUETOOTH_BLUETOOTH_ALLOWED_DEVICES_MAP_H_