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

device/generic_sensor/platform_sensor_provider_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_provider_win.h"
+
+#include "base/memory/singleton.h"
+#include "base/task_runner_util.h"
+#include "base/threading/thread.h"
+#include "device/generic_sensor/platform_sensor_win.h"
+
+namespace device {
+
+// static
+PlatformSensorProvider* PlatformSensorProvider::GetInstance() {
+  return PlatformSensorProviderWin::GetInstance();
+}
+
+// static
+PlatformSensorProviderWin* PlatformSensorProviderWin::GetInstance() {
+  return base::Singleton<
+      PlatformSensorProviderWin,
+      base::LeakySingletonTraits<PlatformSensorProviderWin>>::get();
+}
+
+void PlatformSensorProviderWin::SetSensorManagerForTesting(
+    base::win::ScopedComPtr<ISensorManager> sensor_manager) {
+  sensor_manager_ = sensor_manager;
+}
+
+PlatformSensorProviderWin::PlatformSensorProviderWin() = default;
+PlatformSensorProviderWin::~PlatformSensorProviderWin() = default;
+
+void PlatformSensorProviderWin::CreateSensorInternal(
+    mojom::SensorType type,
+    mojo::ScopedSharedBufferMapping mapping,
+    const CreateSensorCallback& callback) {
+  DCHECK(CalledOnValidThread());
+  if (!StartSensorThread()) {
+    callback.Run(nullptr);
+    return;
+  }
+
+  base::PostTaskAndReplyWithResult(
+      sensor_thread_->task_runner().get(), FROM_HERE,
+      base::Bind(&PlatformSensorProviderWin::CreateSensorReader,
+                 base::Unretained(this), type),
+      base::Bind(&PlatformSensorProviderWin::SensorReaderCreated,
+                 base::Unretained(this), type, base::Passed(&mapping),
+                 callback));
+}
+
+bool PlatformSensorProviderWin::InitializeSensorManager() {
+  if (sensor_manager_)
+    return true;
+
+  HRESULT hr = sensor_manager_.CreateInstance(CLSID_SensorManager);
+  return SUCCEEDED(hr);
+}
+
+void PlatformSensorProviderWin::AllSensorsRemoved() {
+  StopSensorThread();
+}
+
+bool PlatformSensorProviderWin::StartSensorThread() {
+  if (!sensor_thread_) {
+    sensor_thread_ =
+        base::MakeUnique<base::Thread>("Windows platform sensor thread");

[Reilly Grant (use Gerrit), 2016/10/31 21:49:43]

As with the Linux patch, you might as well call this just the sensor thread
since it's obvious that it's the Windows version.

[shalamov, 2016/11/01 11:00:02]

Done.

+    sensor_thread_->init_com_with_mta(true);
+  }
+
+  if (!sensor_thread_->IsRunning())
+    return sensor_thread_->Start();
+  return true;
+}
+
+void PlatformSensorProviderWin::StopSensorThread() {
+  if (sensor_thread_ && sensor_thread_->IsRunning()) {
+    sensor_manager_.Release();
+    sensor_thread_->Stop();
+  }
+}
+
+void PlatformSensorProviderWin::SensorReaderCreated(
+    mojom::SensorType type,
+    mojo::ScopedSharedBufferMapping mapping,
+    const CreateSensorCallback& callback,
+    std::unique_ptr<PlatformSensorReaderWin> sensor_reader) {
+  DCHECK(CalledOnValidThread());
+  if (!sensor_reader) {
+    callback.Run(nullptr);
+    if (!HasSensors())
+      StopSensorThread();
+    return;
+  }
+
+  scoped_refptr<PlatformSensor> sensor = new PlatformSensorWin(
+      type, std::move(mapping), this, sensor_thread_->task_runner(),
+      std::move(sensor_reader));
+  callback.Run(sensor);
+}
+
+std::unique_ptr<PlatformSensorReaderWin>
+PlatformSensorProviderWin::CreateSensorReader(mojom::SensorType type) {
+  DCHECK(sensor_thread_->task_runner()->BelongsToCurrentThread());
+  if (!InitializeSensorManager())
+    return nullptr;
+  return PlatformSensorReaderWin::Create(type, sensor_manager_);
+}
+
+}  // namespace device