[sensors] Introduce asynchronous way to create sensors.

device/generic_sensor/sensor_provider_impl.h

 // 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.
 
 #ifndef DEVICE_GENERIC_SENSOR_SENSOR_PROVIDER_IMPL_H_
 #define DEVICE_GENERIC_SENSOR_SENSOR_PROVIDER_IMPL_H_
 
 #include "base/macros.h"
 #include "device/generic_sensor/public/interfaces/sensor_provider.mojom.h"
 
 namespace device {
 
 class PlatformSensorProvider;
+class PlatformSensor;
 
 // Implementation of SensorProvider mojo interface.
 // Uses PlatformSensorProvider singleton to create platform specific instances
 // of PlatformSensor which are used by SensorImpl.
 class SensorProviderImpl final : public mojom::SensorProvider {
  public:
   static void Create(mojom::SensorProviderRequest request);
 
   ~SensorProviderImpl() override;
 
  private:
   explicit SensorProviderImpl(PlatformSensorProvider* provider);
 
   // SensorProvider implementation.
   void GetSensor(mojom::SensorType type,
                  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);
 };
 
 }  // namespace device
 
 #endif  // DEVICE_GENERIC_SENSOR_SENSOR_PROVIDER_IMPL_H_