Implement DeviceMotionEvent API

chromeos/accelerometer/accelerometer_types.h

 // Copyright 2014 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 CHROMEOS_ACCELEROMETER_ACCELEROMETER_TYPES_H_
 #define CHROMEOS_ACCELEROMETER_ACCELEROMETER_TYPES_H_
 
 #include "base/macros.h"
+#include "base/memory/ref_counted.h"
 #include "chromeos/chromeos_export.h"
 
 namespace chromeos {
 
 enum AccelerometerSource {
   // Accelerometer is located in the device's screen. In the screen's natural
   // orientation, positive X points to the right, consistent with the pixel
   // position. Positive Y points up the screen. Positive Z is perpendicular to
   // the screen, pointing outwards towards the user. The orientation is
   // described at:
@@ skipping 18 matching lines @@
   bool present;
 
   // The readings from this accelerometer measured in m/s^2.
   float x;
   float y;
   float z;
 };
 
 // An accelerometer update contains the last known value for each of the
 // accelerometers present on the device.
-class CHROMEOS_EXPORT AccelerometerUpdate {
+class CHROMEOS_EXPORT AccelerometerUpdate
+    : public base::RefCountedThreadSafe<AccelerometerUpdate> {
  public:
   AccelerometerUpdate();
-  ~AccelerometerUpdate();
 
   // Returns true if |source| has a valid value in this update.
   bool has(AccelerometerSource source) const { return data_[source].present; }
 
   // Returns the last known value for |source|.
   const AccelerometerReading& get(AccelerometerSource source) const {
     return data_[source];
   }
 
   void Set(AccelerometerSource source, float x, float y, float z) {
     data_[source].present = true;
     data_[source].x = x;
     data_[source].y = y;
     data_[source].z = z;
   }
 
  protected:
   AccelerometerReading data_[ACCELEROMETER_SOURCE_COUNT];
 
  private:
+  friend class base::RefCountedThreadSafe<AccelerometerUpdate>;
+
+  virtual ~AccelerometerUpdate();
+
   DISALLOW_COPY_AND_ASSIGN(AccelerometerUpdate);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_ACCELEROMETER_ACCELEROMETER_TYPES_H_