[sensors](Linux) Fix tsan data race in sensor reader

device/generic_sensor/platform_sensor_provider_linux.h

Index: device/generic_sensor/platform_sensor_provider_linux.h
diff --git a/device/generic_sensor/platform_sensor_provider_linux.h b/device/generic_sensor/platform_sensor_provider_linux.h
index 7e15590c40487f14d154e636796475678eefb46f..071adb355119155c08a7be85dbf262c2b7a9ea7d 100644
--- a/device/generic_sensor/platform_sensor_provider_linux.h
+++ b/device/generic_sensor/platform_sensor_provider_linux.h
@@ -17,6 +17,7 @@ class Thread;
 
 namespace device {
 
+class SensorReader;
 struct SensorInfoLinux;
 
 class DEVICE_GENERIC_SENSOR_EXPORT PlatformSensorProviderLinux
@@ -53,11 +54,14 @@ class DEVICE_GENERIC_SENSOR_EXPORT PlatformSensorProviderLinux
 
   PlatformSensorProviderLinux();
 
-  void SensorDeviceFound(
+  // Creates a platform sensor using a sensor reader created on a different
+  // thread.

[Reilly Grant (use Gerrit), 2016/12/14 18:56:08]

*created on |polling_thread_|.

[maksims (do not use this acc), 2016/12/16 08:39:22]

comment removed

+  void SensorReaderCreated(
       mojom::SensorType type,
       mojo::ScopedSharedBufferMapping mapping,
       const PlatformSensorProviderBase::CreateSensorCallback& callback,
-      SensorInfoLinux* sensor_device);
+      SensorInfoLinux* const sensor_device,

[Reilly Grant (use Gerrit), 2016/12/14 18:56:08]

You mean const SensorInfoLinux*.

[maksims (do not use this acc), 2016/12/16 08:39:22]

Done.

+      std::unique_ptr<SensorReader> sensor_reader);
 
   bool StartPollingThread();
 
@@ -80,10 +84,6 @@ class DEVICE_GENERIC_SENSOR_EXPORT PlatformSensorProviderLinux
   // Processed stored requests in |request_map_|.
   void ProcessStoredRequests();
 
-  // Called when sensors are created asynchronously after enumeration is done.
-  void CreateSensorAndNotify(mojom::SensorType type,
-                             SensorInfoLinux* sensor_device);
-
   // SensorDeviceManager::Delegate implements:
   void OnSensorNodesEnumerated() override;
   void OnDeviceAdded(mojom::SensorType type,