[sensors] [win] Implement ambient light sensor for Windows platform

device/generic_sensor/platform_sensor_win.cc

Index: device/generic_sensor/platform_sensor_win.cc
diff --git a/device/generic_sensor/platform_sensor_win.cc b/device/generic_sensor/platform_sensor_win.cc
new file mode 100644
index 0000000000000000000000000000000000000000..b9234376e7d7ccdf61f2dc48944b2e5e4f24220b
--- /dev/null
+++ b/device/generic_sensor/platform_sensor_win.cc
@@ -0,0 +1,76 @@
+// 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 {
+const double kDefaultSensorReportingFrequency = 5.0;

[Lei Zhang, 2016/10/29 05:10:42]

constexpr

[shalamov, 2016/10/31 13:12:58]

Done.

+}  // namespace
+
+PlatformSensorWin::PlatformSensorWin(
+    mojom::SensorType type,
+    mojo::ScopedSharedBufferMapping mapping,
+    PlatformSensorProvider* provider,
+    scoped_refptr<base::SingleThreadTaskRunner> sensor_thread_runner,
+    std::unique_ptr<PlatformSensorReaderWin> sensor_reader)
+    : PlatformSensor(type, std::move(mapping), provider),
+      sensor_thread_runner_(sensor_thread_runner),
+      sensor_reader_(std::move(sensor_reader)),
+      weak_factory_(this) {
+  DCHECK(sensor_reader_);
+  sensor_reader_->SetClient(this);
+}
+
+PlatformSensorConfiguration PlatformSensorWin::GetDefaultConfiguration() {
+  return PlatformSensorConfiguration(kDefaultSensorReportingFrequency);
+}
+
+mojom::ReportingMode PlatformSensorWin::GetReportingMode() {
+  DCHECK(sensor_reader_);

[Lei Zhang, 2016/10/29 05:10:42]

Already checked in the ctor.

[shalamov, 2016/10/31 13:12:58]

Done.

+  return sensor_reader_->GetReportingMode();
+}
+
+void PlatformSensorWin::OnReadingUpdated(const SensorReading& reading) {
+  UpdateSensorReading(reading,
+                      GetReportingMode() == mojom::ReportingMode::ON_CHANGE);
+}
+
+void PlatformSensorWin::OnSensorError() {
+  task_runner_->PostTask(FROM_HERE,
+                         base::Bind(&PlatformSensorWin::NotifySensorError,
+                                    weak_factory_.GetWeakPtr()));
+}
+
+bool PlatformSensorWin::StartSensor(
+    const PlatformSensorConfiguration& configuration) {
+  DCHECK(task_runner_->BelongsToCurrentThread());
+  return sensor_reader_->StartSensor(configuration);
+}
+
+void PlatformSensorWin::StopSensor() {
+  DCHECK(task_runner_->BelongsToCurrentThread());
+  sensor_reader_->StopSensor();
+}
+
+bool PlatformSensorWin::CheckSensorConfiguration(
+    const PlatformSensorConfiguration& configuration) {
+  DCHECK(sensor_reader_);

[Lei Zhang, 2016/10/29 05:10:42]

Already checked in the ctor, plus we usually make sure we are on the right
thread first before doing other checks.

[shalamov, 2016/10/31 13:12:58]

Done.

+  DCHECK(task_runner_->BelongsToCurrentThread());
+  double minimal_reporting_interval_ms =
+      sensor_reader_->GetMinimalReportingIntervalMs();
+  if (minimal_reporting_interval_ms == 0)
+    return true;
+  double min_frequency =
+      1 / (minimal_reporting_interval_ms / base::Time::kMillisecondsPerSecond);

[Lei Zhang, 2016/10/29 05:10:42]

Why can't this be just: kMillisecondsPerSecond / interval_ms ?

[shalamov, 2016/10/31 13:12:58]

Done.

+  return configuration.frequency() <= min_frequency;
+}
+
+PlatformSensorWin::~PlatformSensorWin() {
+  sensor_reader_->SetClient(nullptr);
+  sensor_thread_runner_->DeleteSoon(FROM_HERE, sensor_reader_.release());
+}
+
+}  // namespace device