[sensors] Add GetDefaultConfiguration() to generic sensor mojo interface.

device/generic_sensor/platform_sensor.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 DEVICE_GENERIC_SENSOR_PLATFORM_SENSOR_H_
 #define DEVICE_GENERIC_SENSOR_PLATFORM_SENSOR_H_
 
 #include <list>
 #include <map>
 
@@ skipping 18 matching lines @@
    public:
     virtual void OnSensorReadingChanged() = 0;
     virtual void OnSensorError() = 0;
     virtual bool IsNotificationSuspended() = 0;
 
    protected:
     virtual ~Client() {}
   };
 
   virtual mojom::ReportingMode GetReportingMode() = 0;
+  virtual PlatformSensorConfiguration GetDefaultConfiguration() = 0;
 
   mojom::SensorType GetType() const;
 
   bool StartListening(Client* client,
                       const PlatformSensorConfiguration& config);
   bool StopListening(Client* client, const PlatformSensorConfiguration& config);
 
   void UpdateSensor();
 
   void AddClient(Client*);
@@ skipping 23 matching lines @@
   base::ObserverList<Client, true> clients_;
   ConfigMap config_map_;
   PlatformSensorProvider* provider_;
   base::WeakPtrFactory<PlatformSensor> weak_factory_;
   DISALLOW_COPY_AND_ASSIGN(PlatformSensor);
 };
 
 }  // namespace device
 
 #endif  // DEVICE_GENERIC_SENSOR_PLATFORM_SENSOR_H_