Add signal strength indicator icon to WebBluetooth chooser on non-Mac desktops

content/browser/bluetooth/bluetooth_device_chooser_controller.h

 // Copyright 2016 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_DEVICE_CHOOSER_CONTROLLER_H_
 #define CONTENT_BROWSER_BLUETOOTH_BLUETOOTH_DEVICE_CHOOSER_CONTROLLER_H_
 
 #include <string>
 
 #include "base/memory/weak_ptr.h"
@@ skipping 60 matching lines @@
       const ErrorCallback& error_callback);
 
   // Adds a device to the chooser. Should only be called after GetDevice and
   // before either of the callbacks are run.
   void AddFilteredDevice(const device::BluetoothDevice& device);
 
   // Stops the current discovery session and notifies the chooser
   // that the adapter changed states.
   void AdapterPoweredChanged(bool powered);
 
+  // Received Signal Strength Indicator (RSSI) is a measurement of the power
+  // present in a received radio signal.
+  static int CalculateSignalStrengthLevel(int8_t rssi);
+
   // After this method is called any new instance of
   // BluetoothDeviceChooserController will have a scan duration of 0.
   static void SetTestScanDurationForTesting();
 
  private:
   // Populates the chooser with the GATT connected devices.
   void PopulateConnectedDevices();
 
   // Notifies the chooser that discovery is starting and starts a discovery
   // session.
@@ skipping 54 matching lines @@
   // Weak pointer factory for generating 'this' pointers that might live longer
   // than we do.
   // Note: This should remain the last member so it'll be destroyed and
   // invalidate its weak pointers before any other members are destroyed.
   base::WeakPtrFactory<BluetoothDeviceChooserController> weak_ptr_factory_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_BLUETOOTH_BLUETOOTH_DEVICE_CHOOSER_CONTROLLER_H_