[sensors](CrOS/Linux) Implement Sensor device manager for sensors

device/generic_sensor/platform_sensor_provider_base.h

Index: device/generic_sensor/platform_sensor_provider_base.h
diff --git a/device/generic_sensor/platform_sensor_provider_base.h b/device/generic_sensor/platform_sensor_provider_base.h
index b6c33b1e29b71daa56109fbee0d08119455f37a1..a94918beffe6a57f9071557399850c3c4d8e61fc 100644
--- a/device/generic_sensor/platform_sensor_provider_base.h
+++ b/device/generic_sensor/platform_sensor_provider_base.h
@@ -53,13 +53,23 @@ class DEVICE_GENERIC_SENSOR_EXPORT PlatformSensorProviderBase
   // are no sensors left.
   virtual void AllSensorsRemoved() {}
 
+  // Implementations might override this method to know what type of sensor
+  // has been removed.
+  virtual void SensorRemoved(mojom::SensorType type) {}
+
+  void NotifySensorCreated(mojom::SensorType type,
+                           scoped_refptr<PlatformSensor> sensor);
+
+  std::vector<mojom::SensorType> GetPendingRequestTypes();
+
+  mojo::ScopedSharedBufferMapping GetScopedSharedBufferMapping(
+      mojom::SensorType type);
+
  private:
   friend class PlatformSensor;  // To call RemoveSensor();
 
   bool CreateSharedBufferIfNeeded();
   void RemoveSensor(mojom::SensorType type);
-  void NotifySensorCreated(mojom::SensorType type,
-                           scoped_refptr<PlatformSensor> sensor);
 
  private:
   using CallbackQueue = std::vector<CreateSensorCallback>;