[sensors][win] Implementation of motion sensors for Win platform

device/generic_sensor/platform_sensor_win.cc

 // 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/platform_sensor_win.h"
 
 namespace device {
 
 namespace {
 constexpr double kDefaultSensorReportingFrequency = 5.0;
@@ skipping 11 matching lines @@
       weak_factory_(this) {
   DCHECK(sensor_reader_);
   sensor_reader_->SetClient(this);
 }
 
 PlatformSensorConfiguration PlatformSensorWin::GetDefaultConfiguration() {
   return PlatformSensorConfiguration(kDefaultSensorReportingFrequency);
 }
 
 mojom::ReportingMode PlatformSensorWin::GetReportingMode() {
-  return sensor_reader_->GetReportingMode();
+  // All Windows sensors, even with high accuracy / sensitivity will not report
+  // reading updates continuously. Therefore, return ON_CHANGE by default.
+  return mojom::ReportingMode::ON_CHANGE;
 }
 
 double PlatformSensorWin::GetMaximumSupportedFrequency() {
   double minimal_reporting_interval_ms =
       sensor_reader_->GetMinimalReportingIntervalMs();
   if (!minimal_reporting_interval_ms)
     return kDefaultSensorReportingFrequency;
   return base::Time::kMillisecondsPerSecond / minimal_reporting_interval_ms;
 }
 
 void PlatformSensorWin::OnReadingUpdated(const SensorReading& reading) {
-  UpdateSensorReading(reading,
-                      GetReportingMode() == mojom::ReportingMode::ON_CHANGE);
+  // Default reporting mode is ON_CHANGE, thus, set notify_clients parameter
+  // to true.
+  UpdateSensorReading(reading, true);
 }
 
 void PlatformSensorWin::OnSensorError() {
   task_runner_->PostTask(FROM_HERE,
                          base::Bind(&PlatformSensorWin::NotifySensorError,
                                     weak_factory_.GetWeakPtr()));
 }
 
 bool PlatformSensorWin::StartSensor(
     const PlatformSensorConfiguration& configuration) {
@@ skipping 17 matching lines @@
       base::Time::kMillisecondsPerSecond / minimal_reporting_interval_ms;
   return configuration.frequency() <= max_frequency;
 }
 
 PlatformSensorWin::~PlatformSensorWin() {
   sensor_reader_->SetClient(nullptr);
   sensor_thread_runner_->DeleteSoon(FROM_HERE, sensor_reader_);
 }
 
 }  // namespace device