Revert of Move //device/generic_sensor to be part of the internal implementation of the Device Service.

device/generic_sensor/platform_sensor_provider_base.h

Index: device/generic_sensor/platform_sensor_provider_base.h
diff --git a/device/generic_sensor/platform_sensor_provider_base.h b/device/generic_sensor/platform_sensor_provider_base.h
new file mode 100644
index 0000000000000000000000000000000000000000..c38443bee899d568c2d020fe85112834ec1aca58
--- /dev/null
+++ b/device/generic_sensor/platform_sensor_provider_base.h
@@ -0,0 +1,84 @@
+// 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_PLATFORM_SENSOR_PROVIDER_BASE_H_
+#define DEVICE_GENERIC_SENSOR_PLATFORM_SENSOR_PROVIDER_BASE_H_
+
+#include "base/macros.h"
+
+#include "base/single_thread_task_runner.h"
+#include "base/threading/thread_checker.h"
+#include "device/generic_sensor/generic_sensor_export.h"
+#include "device/generic_sensor/platform_sensor.h"
+
+namespace device {
+
+// Base class that defines factory methods for PlatformSensor creation.
+// Its implementations must be accessed via GetInstance() method.
+class DEVICE_GENERIC_SENSOR_EXPORT PlatformSensorProviderBase {
+ public:
+  using CreateSensorCallback =
+      base::Callback<void(scoped_refptr<PlatformSensor>)>;
+
+  // Creates new instance of PlatformSensor.
+  void CreateSensor(mojom::SensorType type,
+                    const CreateSensorCallback& callback);
+
+  // Gets previously created instance of PlatformSensor by sensor type |type|.
+  scoped_refptr<PlatformSensor> GetSensor(mojom::SensorType type);
+
+  // Shared buffer getters.
+  mojo::ScopedSharedBufferHandle CloneSharedBufferHandle();
+
+  // Returns 'true' if some of sensor instances produced by this provider are
+  // alive; 'false' otherwise.
+  bool HasSensors() const;
+
+  // Implementations might want to override this in order to be able
+  // to read from sensor files. For example, linux does so.
+  virtual void SetFileTaskRunner(
+      scoped_refptr<base::SingleThreadTaskRunner> file_task_runner) {}
+
+ protected:
+  PlatformSensorProviderBase();
+  virtual ~PlatformSensorProviderBase();
+
+  // Method that must be implemented by platform specific classes.
+  virtual void CreateSensorInternal(mojom::SensorType type,
+                                    mojo::ScopedSharedBufferMapping mapping,
+                                    const CreateSensorCallback& callback) = 0;
+
+  // Implementations might override this method to free resources when there
+  // are no sensors left.
+  virtual void AllSensorsRemoved() {}
+
+  void NotifySensorCreated(mojom::SensorType type,
+                           scoped_refptr<PlatformSensor> sensor);
+
+  std::vector<mojom::SensorType> GetPendingRequestTypes();
+
+  mojo::ScopedSharedBufferMapping MapSharedBufferForType(
+      mojom::SensorType type);
+
+  THREAD_CHECKER(thread_checker_);
+
+ private:
+  friend class PlatformSensor;  // To call RemoveSensor();
+
+  bool CreateSharedBufferIfNeeded();
+  void RemoveSensor(mojom::SensorType type);
+
+ private:
+  using CallbackQueue = std::vector<CreateSensorCallback>;
+
+  std::map<mojom::SensorType, PlatformSensor*> sensor_map_;
+  std::map<mojom::SensorType, CallbackQueue> requests_map_;
+  mojo::ScopedSharedBufferHandle shared_buffer_handle_;
+
+  DISALLOW_COPY_AND_ASSIGN(PlatformSensorProviderBase);
+};
+
+}  // namespace device
+
+#endif  // DEVICE_GENERIC_SENSOR_PLATFORM_SENSOR_PROVIDER_BASE_H_