Add RELATIVE_ORIENTATION sensor implementation on macOS to //device/generic_sensor

device/generic_sensor/platform_sensor.h

Index: device/generic_sensor/platform_sensor.h
diff --git a/device/generic_sensor/platform_sensor.h b/device/generic_sensor/platform_sensor.h
index 94629a552b9d9abe55556bce46e78145afa448c5..07a12b37af3a892202068c2de0e6017efce9ef7a 100644
--- a/device/generic_sensor/platform_sensor.h
+++ b/device/generic_sensor/platform_sensor.h
@@ -41,6 +41,11 @@ class DEVICE_GENERIC_SENSOR_EXPORT PlatformSensor
 
   virtual mojom::ReportingMode GetReportingMode() = 0;
   virtual PlatformSensorConfiguration GetDefaultConfiguration() = 0;
+  virtual bool StartSensor(
+      const PlatformSensorConfiguration& configuration) = 0;
+  virtual void StopSensor() = 0;
+  virtual bool CheckSensorConfiguration(
+      const PlatformSensorConfiguration& configuration) = 0;
 
   // Can be overriden to return the sensor maximum sampling frequency
   // value obtained from the platform if it is available. If platfrom
@@ -64,6 +69,8 @@ class DEVICE_GENERIC_SENSOR_EXPORT PlatformSensor
   void AddClient(Client*);
   void RemoveClient(Client*);
 
+  bool GetLatestReading(SensorReading* result);

[Mikhail, 2017/06/21 11:10:00]

let's make it virtual, it seems the newly added
PlatformSensorFusionRelativeOrientation should override it.

[juncai, 2017/07/20 00:22:16]

Not sure why makes it virtual. It should be the same for all subclasses of
PlatformSensor.

+
  protected:
   virtual ~PlatformSensor();
   PlatformSensor(mojom::SensorType type,
@@ -74,11 +81,6 @@ class DEVICE_GENERIC_SENSOR_EXPORT PlatformSensor
   using ReadingBuffer = SensorReadingSharedBuffer;
 
   virtual bool UpdateSensorInternal(const ConfigMap& configurations);
-  virtual bool StartSensor(
-      const PlatformSensorConfiguration& configuration) = 0;
-  virtual void StopSensor() = 0;
-  virtual bool CheckSensorConfiguration(
-      const PlatformSensorConfiguration& configuration) = 0;
 
   // Updates shared buffer with new sensor reading data.
   // Note: this method is thread-safe.
@@ -94,12 +96,12 @@ class DEVICE_GENERIC_SENSOR_EXPORT PlatformSensor
   // If platfrom sensor events are processed on a different
   // thread, notifications are forwarded to |task_runner_|.
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+  base::ObserverList<Client, true> clients_;
 
  private:
   friend class base::RefCountedThreadSafe<PlatformSensor>;
   const mojo::ScopedSharedBufferMapping shared_buffer_mapping_;
   mojom::SensorType type_;
-  base::ObserverList<Client, true> clients_;
   ConfigMap config_map_;
   PlatformSensorProvider* provider_;
   base::WeakPtrFactory<PlatformSensor> weak_factory_;