[sensors] Introduce asynchronous way to create sensors.

device/generic_sensor/sensor_provider_impl.h

Index: device/generic_sensor/sensor_provider_impl.h
diff --git a/device/generic_sensor/sensor_provider_impl.h b/device/generic_sensor/sensor_provider_impl.h
index b46d59ac5224f0579408b1e3e2a046ed9dbdaae9..1a298e39e9c83e8920ae7a00b92ee35a6908bf2b 100644
--- a/device/generic_sensor/sensor_provider_impl.h
+++ b/device/generic_sensor/sensor_provider_impl.h
@@ -11,6 +11,7 @@
 namespace device {
 
 class PlatformSensorProvider;
+class PlatformSensor;
 
 // Implementation of SensorProvider mojo interface.
 // Uses PlatformSensorProvider singleton to create platform specific instances
@@ -29,8 +30,20 @@ class SensorProviderImpl final : public mojom::SensorProvider {
                  mojom::SensorRequest sensor_request,
                  const GetSensorCallback& callback) override;
 
+  // Helper callback method to create sensors.
+  void CreateSensor(mojom::SensorType type,
+                    mojo::ScopedSharedBufferHandle cloned_handle,
+                    mojom::SensorRequest sensor_request,
+                    const GetSensorCallback& callback,
+                    scoped_refptr<PlatformSensor> sensor);
+
+  using CreateSensorCallback =

[Mikhail, 2016/09/26 09:52:23]

we don't need it in this header.

[maksims (do not use this acc), 2016/09/27 10:17:25]

Done.

+      base::Callback<void(scoped_refptr<PlatformSensor>)>;
+
   PlatformSensorProvider* provider_;
 
+  base::WeakPtrFactory<SensorProviderImpl> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(SensorProviderImpl);
 };