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

device/generic_sensor/platform_sensor.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.h"
+
+#include <utility>
+
+#include "base/threading/thread_task_runner_handle.h"
+#include "device/generic_sensor/platform_sensor_provider.h"
+#include "device/generic_sensor/public/cpp/platform_sensor_configuration.h"
+
+namespace device {
+
+PlatformSensor::PlatformSensor(mojom::SensorType type,
+                               mojo::ScopedSharedBufferMapping mapping,
+                               PlatformSensorProvider* provider)
+    : task_runner_(base::ThreadTaskRunnerHandle::Get()),
+      shared_buffer_mapping_(std::move(mapping)),
+      type_(type),
+      provider_(provider),
+      weak_factory_(this) {}
+
+PlatformSensor::~PlatformSensor() {
+  provider_->RemoveSensor(GetType());
+}
+
+mojom::SensorType PlatformSensor::GetType() const {
+  return type_;
+}
+
+double PlatformSensor::GetMaximumSupportedFrequency() {
+  return GetDefaultConfiguration().frequency();
+}
+
+double PlatformSensor::GetMinimumSupportedFrequency() {
+  return 1.0 / (60 * 60);
+}
+
+bool PlatformSensor::StartListening(Client* client,
+                                    const PlatformSensorConfiguration& config) {
+  DCHECK(clients_.HasObserver(client));
+  if (!CheckSensorConfiguration(config))
+    return false;
+
+  auto& config_list = config_map_[client];
+  config_list.push_back(config);
+
+  if (!UpdateSensorInternal(config_map_)) {
+    config_list.pop_back();
+    return false;
+  }
+
+  return true;
+}
+
+bool PlatformSensor::StopListening(Client* client,
+                                   const PlatformSensorConfiguration& config) {
+  DCHECK(clients_.HasObserver(client));
+  auto client_entry = config_map_.find(client);
+  if (client_entry == config_map_.end())
+    return false;
+
+  auto& config_list = client_entry->second;
+  auto config_entry = std::find(config_list.begin(), config_list.end(), config);
+  if (config_entry == config_list.end())
+    return false;
+
+  config_list.erase(config_entry);
+
+  return UpdateSensorInternal(config_map_);
+}
+
+void PlatformSensor::UpdateSensor() {
+  UpdateSensorInternal(config_map_);
+}
+
+void PlatformSensor::AddClient(Client* client) {
+  DCHECK(client);
+  clients_.AddObserver(client);
+}
+
+void PlatformSensor::RemoveClient(Client* client) {
+  DCHECK(client);
+  clients_.RemoveObserver(client);
+  auto client_entry = config_map_.find(client);
+  if (client_entry != config_map_.end()) {
+    config_map_.erase(client_entry);
+    UpdateSensorInternal(config_map_);
+  }
+}
+
+void PlatformSensor::UpdateSensorReading(const SensorReading& reading,
+                                         bool notify_clients) {
+  ReadingBuffer* buffer =
+      static_cast<ReadingBuffer*>(shared_buffer_mapping_.get());
+  auto& seqlock = buffer->seqlock.value();
+  seqlock.WriteBegin();
+  buffer->reading = reading;
+  seqlock.WriteEnd();
+
+  if (notify_clients)
+    task_runner_->PostTask(
+        FROM_HERE, base::Bind(&PlatformSensor::NotifySensorReadingChanged,
+                              weak_factory_.GetWeakPtr()));
+}
+
+void PlatformSensor::NotifySensorReadingChanged() {
+  for (auto& client : clients_) {
+    if (!client.IsNotificationSuspended())
+      client.OnSensorReadingChanged();
+  }
+}
+
+void PlatformSensor::NotifySensorError() {
+  for (auto& observer : clients_)
+    observer.OnSensorError();
+}
+
+bool PlatformSensor::UpdateSensorInternal(const ConfigMap& configurations) {
+  const PlatformSensorConfiguration* optimal_configuration = nullptr;
+  for (const auto& pair : configurations) {
+    if (pair.first->IsNotificationSuspended())
+      continue;
+
+    const auto& conf_list = pair.second;
+    for (const auto& configuration : conf_list) {
+      if (!optimal_configuration || configuration > *optimal_configuration) {
+        optimal_configuration = &configuration;
+      }
+    }
+  }
+
+  if (!optimal_configuration) {
+    StopSensor();
+    return true;
+  }
+
+  return StartSensor(*optimal_configuration);
+}
+
+}  // namespace device