[Sensors] Improvements in shared buffer managing

device/generic_sensor/public/cpp/sensor_reading.cc

Index: device/generic_sensor/public/cpp/sensor_reading.cc
diff --git a/device/generic_sensor/public/cpp/sensor_reading.cc b/device/generic_sensor/public/cpp/sensor_reading.cc
new file mode 100644
index 0000000000000000000000000000000000000000..055b39a7d70ead4679c4fd20d0f6aa69d10452cd
--- /dev/null
+++ b/device/generic_sensor/public/cpp/sensor_reading.cc
@@ -0,0 +1,14 @@
+// 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.
+
+#include "device/generic_sensor/public/cpp/sensor_reading.h"
+
+namespace device {
+
+SensorReading::SensorReading() = default;
+SensorReading::SensorReading(const SensorReading& other) = default;
+
+SensorReadingSharedBuffer::SensorReadingSharedBuffer() = default;
+
+}  // namespace device