Device Orientation API on Chrome OS

content/browser/device_sensors/sensor_manager_chromeos.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_DEVICE_SENSORS_SENSOR_MANAGER_CHROMEOS_H_
+#define CONTENT_BROWSER_DEVICE_SENSORS_SENSOR_MANAGER_CHROMEOS_H_
+
+#include "base/macros.h"
+#include "base/synchronization/lock.h"
+#include "chromeos/accelerometer/accelerometer_reader.h"
+#include "chromeos/accelerometer/accelerometer_types.h"
+#include "content/common/content_export.h"
+#include "content/common/device_sensors/device_orientation_hardware_buffer.h"
+
+namespace content {
+
+// Observes Chrome OS accelerometer sensors, and provides updated device
+// orientation information.
+class CONTENT_EXPORT SensorManagerChromeOS
+    : public chromeos::AccelerometerReader::Observer {
+ public:
+  SensorManagerChromeOS();
+  ~SensorManagerChromeOS() override;
+
+  // Begins monitoring of orientation events, the shared memory of |buffer| will
+  // be updated upon subsequent events.
+  bool StartFetchingDeviceOrientationData(
+      DeviceOrientationHardwareBuffer* buffer);
+
+  // Stops monitoring orientation events. Returns true if there is an active
+  // |orientation_buffer_| and fetching stops. Otherwise returns false.
+  bool StopFetchingDeviceOrientationData();
+
+  // chromeos::AccelerometerReader::Observer:
+  void OnAccelerometerUpdated(
+      const chromeos::AccelerometerUpdate& update) override;
+
+ protected:
+  // Begins/ends the observation of accelerometer events.
+  virtual void StartObservingAccelerometer();
+  virtual void StopObservingAccelerometer();
+
+ private:
+  // Shared memory to update.
+  DeviceOrientationHardwareBuffer* orientation_buffer_;
+
+  // Synchronize orientation_buffer_ across threads.
+  base::Lock orientation_buffer_lock_;
+
+  DISALLOW_COPY_AND_ASSIGN(SensorManagerChromeOS);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_DEVICE_SENSORS_SENSOR_MANAGER_CHROMEOS_H_