[sensors](CrOS/Linux) Implement Sensor device manager for sensors

device/generic_sensor/platform_sensor_provider_linux.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_linux.h"
 
 #include "base/memory/singleton.h"
-#include "base/task_runner_util.h"
 #include "base/threading/thread.h"
-#include "device/generic_sensor/linux/platform_sensor_utils_linux.h"
-#include "device/generic_sensor/linux/sensor_data_linux.h"
 #include "device/generic_sensor/platform_sensor_linux.h"
+#include "device/generic_sensor/platform_sensor_manager_linux.h"
 
 namespace device {
 
 // static
 PlatformSensorProviderLinux* PlatformSensorProviderLinux::GetInstance() {
   return base::Singleton<
       PlatformSensorProviderLinux,
       base::LeakySingletonTraits<PlatformSensorProviderLinux>>::get();
 }
 
 PlatformSensorProviderLinux::PlatformSensorProviderLinux() = default;
 
 PlatformSensorProviderLinux::~PlatformSensorProviderLinux() = default;
 
 void PlatformSensorProviderLinux::CreateSensorInternal(
     mojom::SensorType type,
     mojo::ScopedSharedBufferMapping mapping,
     const CreateSensorCallback& callback) {
-  SensorDataLinux data;
-  if (!InitSensorData(type, &data)) {
-    callback.Run(nullptr);
-    return;
-  }
+  DCHECK(sensor_device_manager_);
 
-  if (!polling_thread_)
-    polling_thread_.reset(new base::Thread("Sensor polling thread"));
+  SensorDeviceManager::GetSensorDeviceCallback cb = base::Bind(
+      &PlatformSensorProviderLinux::SensorDeviceFound, base::Unretained(this),
+      type, base::Passed(&mapping), callback);
 
-  if (!polling_thread_->IsRunning()) {
-    if (!polling_thread_->StartWithOptions(
-            base::Thread::Options(base::MessageLoop::TYPE_IO, 0))) {
-      callback.Run(nullptr);
-      return;
-    }
-    polling_thread_task_runner_ = polling_thread_->task_runner();
-  }
-
-  base::PostTaskAndReplyWithResult(
-      polling_thread_task_runner_.get(), FROM_HERE,
-      base::Bind(SensorReader::Create, data),
-      base::Bind(&PlatformSensorProviderLinux::SensorReaderFound,
-                 base::Unretained(this), type, base::Passed(&mapping), callback,
-                 data));
+  sensor_device_manager_->GetSensorDevice(type, cb);
 }
 
-void PlatformSensorProviderLinux::SensorReaderFound(
+void PlatformSensorProviderLinux::SensorDeviceFound(
     mojom::SensorType type,
     mojo::ScopedSharedBufferMapping mapping,
     const PlatformSensorProviderBase::CreateSensorCallback& callback,
-    const SensorDataLinux& data,
-    std::unique_ptr<SensorReader> sensor_reader) {
+    SensorDeviceLinux* sensor_device) {
   DCHECK(CalledOnValidThread());
 
-  if (!sensor_reader) {
+  if (!sensor_device) {
     // If there are no sensors, stop polling thread.
     if (!HasSensors())
       AllSensorsRemoved();
     callback.Run(nullptr);
     return;
   }
 
-  callback.Run(new PlatformSensorLinux(type, std::move(mapping), this, data,
-                                       std::move(sensor_reader),
-                                       polling_thread_task_runner_));
+  if (!StartPollingThread()) {
+    callback.Run(nullptr);
+    return;
+  }
+
+  callback.Run(new PlatformSensorLinux(type, std::move(mapping), this,
+                                       sensor_device,
+                                       polling_thread_->task_runner()));
 }
 
 void PlatformSensorProviderLinux::SetFileTaskRunner(
     scoped_refptr<base::SingleThreadTaskRunner> file_task_runner) {
   DCHECK(CalledOnValidThread());
-  if (!file_task_runner_)
-    file_task_runner_ = file_task_runner;
+  file_task_runner_ = file_task_runner;

[Mikhail, 2016/11/30 12:29:36]

runner should not be reset in runtime, otherwise scheduled tasks will be lost.

[maksims (do not use this acc), 2016/12/05 13:06:59]

Done.

+  InitializeSensorDeviceManager();
+}
+
+void PlatformSensorProviderLinux::SetSensorDeviceServiceForTesting(
+    std::unique_ptr<SensorDeviceService> device) {
+  DCHECK(sensor_device_manager_);
+  sensor_device_manager_->SetSensorDeviceServiceForTesting(std::move(device));
 }
 
 void PlatformSensorProviderLinux::AllSensorsRemoved() {
   DCHECK(CalledOnValidThread());
   DCHECK(file_task_runner_);
+  sensor_device_manager_->Shutdown();
   // When there are no sensors left, the polling thread must be stopped.
-  // Stop() can only be called on a different thread that allows io.
+  // Stop() can only be called on a different thread that allows I/O.
   // Thus, browser's file thread is used for this purpose.
   file_task_runner_->PostTask(
       FROM_HERE, base::Bind(&PlatformSensorProviderLinux::StopPollingThread,
                             base::Unretained(this)));
 }
 
+bool PlatformSensorProviderLinux::StartPollingThread() {
+  if (!polling_thread_)
+    polling_thread_.reset(new base::Thread("Sensor polling thread"));
+
+  if (!polling_thread_->IsRunning()) {
+    return polling_thread_->StartWithOptions(
+        base::Thread::Options(base::MessageLoop::TYPE_IO, 0));
+  }
+  return true;
+}
+
 void PlatformSensorProviderLinux::StopPollingThread() {
   DCHECK(file_task_runner_);
   DCHECK(file_task_runner_->BelongsToCurrentThread());
-  polling_thread_->Stop();
+  if (polling_thread_ && polling_thread_->IsRunning())
+    polling_thread_->Stop();
+}
+
+void PlatformSensorProviderLinux::InitializeSensorDeviceManager() {
+  if (!sensor_device_manager_)
+    sensor_device_manager_.reset(new SensorDeviceManager());
+  sensor_device_manager_->SetBlockingTaskRunner(file_task_runner_);
 }
 
 }  // namespace device