[sensors] [win] Fix ambient light not working properly Windows 10.

device/generic_sensor/platform_sensor_reader_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_reader_win.h"
 
 #include <Sensors.h>
 
 #include "base/callback.h"
 #include "base/time/time.h"
@@ skipping 224 matching lines @@
 }
 
 PlatformSensorReaderWin::PlatformSensorReaderWin(
     base::win::ScopedComPtr<ISensor> sensor,
     std::unique_ptr<ReaderInitParams> params)
     : init_params_(std::move(params)),
       task_runner_(base::ThreadTaskRunnerHandle::Get()),
       sensor_active_(false),
       client_(nullptr),
       sensor_(sensor),
-      event_listener_(new EventListener(this)) {
+      event_listener_(new EventListener(this)),
+      weak_factory_(this) {
   DCHECK(init_params_);
   DCHECK(!init_params_->reader_func.is_null());
   DCHECK(sensor_);
 }
 
 void PlatformSensorReaderWin::SetClient(Client* client) {
   base::AutoLock autolock(lock_);
   // Can be null.
   client_ = client;
 }
@@ skipping 10 matching lines @@
   DCHECK(task_runner_->BelongsToCurrentThread());
 }
 
 bool PlatformSensorReaderWin::StartSensor(
     const PlatformSensorConfiguration& configuration) {
   base::AutoLock autolock(lock_);
 
   if (!SetReportingInterval(configuration))
     return false;
 
-  // Set event listener.
   if (!sensor_active_) {
-    base::win::ScopedComPtr<ISensorEvents> sensor_events;
-    HRESULT hr = event_listener_->QueryInterface(__uuidof(ISensorEvents),
-                                                 sensor_events.ReceiveVoid());
-
-    if (FAILED(hr) || !sensor_events)
-      return false;
-
-    if (FAILED(sensor_->SetEventSink(sensor_events.get())))
-      return false;
-
-    sensor_active_ = true;
+    task_runner_->PostTask(
+        FROM_HERE, base::Bind(&PlatformSensorReaderWin::ListenSensorEvent,
+                              weak_factory_.GetWeakPtr()));
   }
 
   return true;
 }
 
+void PlatformSensorReaderWin::ListenSensorEvent() {
+  base::AutoLock autolock(lock_);

[shalamov, 2016/11/15 07:31:19]

If it is accessed only on sensor thread, I think you can remove lock.

+  event_listener_->AddRef();
+  // Set event listener.
+  if (FAILED(sensor_->SetEventSink(event_listener_.get()))) {
+    SensorError();
+    StopSensor();
+  }
+  sensor_active_ = true;

[shalamov, 2016/11/15 07:31:19]

Should this be moved to:

if (!sensor_active_) {
  postTask();
  sensor_active_ = true;
}

then, 

if (FAILED(...)) {
  ...
  sensor_active_ = false;
}

Otherwise, we can post multiple tasks for ListenSensorEvent()

+}
+
 bool PlatformSensorReaderWin::SetReportingInterval(
     const PlatformSensorConfiguration& configuration) {
   base::win::ScopedComPtr<IPortableDeviceValues> props;
   if (SUCCEEDED(props.CreateInstance(CLSID_PortableDeviceValues))) {
     unsigned interval =
         (1 / configuration.frequency()) * base::Time::kMillisecondsPerSecond;
 
     HRESULT hr = props->SetUnsignedIntegerValue(
         SENSOR_PROPERTY_CURRENT_REPORT_INTERVAL, interval);
 
@@ skipping 25 matching lines @@
 
 unsigned long PlatformSensorReaderWin::GetMinimalReportingIntervalMs() const {
   return init_params_->min_reporting_interval_ms;
 }
 
 mojom::ReportingMode PlatformSensorReaderWin::GetReportingMode() const {
   return init_params_->reporting_mode;
 }
 
 }  // namespace device