content: Cleanup class/struct forward declarations

content/browser/bluetooth/bluetooth_metrics.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_METRICS_H_
 #define CONTENT_BROWSER_BLUETOOTH_BLUETOOTH_METRICS_H_
 
 #include <string>
 #include <vector>
 
 #include "third_party/WebKit/public/platform/modules/bluetooth/web_bluetooth.mojom.h"
 
 namespace base {
 class TimeDelta;
 }
 
 namespace device {
 class BluetoothUUID;
 }
 
 namespace content {
-struct BluetoothScanFilter;
 
 // General Metrics
 
 // Enumeration of each Web Bluetooth API entry point.
 enum class UMAWebBluetoothFunction {
   REQUEST_DEVICE = 0,
   CONNECT_GATT = 1,
   GET_PRIMARY_SERVICE = 2,
   SERVICE_GET_CHARACTERISTIC = 3,
   CHARACTERISTIC_READ_VALUE = 4,
@@ skipping 257 matching lines @@
 
 // Records the raw RSSI, and processed result displayed to users, when
 // content::BluetoothDeviceChooserController::CalculateSignalStrengthLevel() is
 // called.
 void RecordRSSISignalStrength(int rssi);
 void RecordRSSISignalStrengthLevel(UMARSSISignalStrengthLevel level);
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_BLUETOOTH_BLUETOOTH_METRICS_H_