Add RELATIVE_ORIENTATION sensor implementation on macOS to //device/generic_sensor

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"
@@ skipping 72 matching lines @@
 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_);
   }
 }
 
+bool PlatformSensor::GetLatestReading(SensorReading* result) {
+  const SensorReadingSharedBuffer* buffer =
+      static_cast<const SensorReadingSharedBuffer*>(
+          shared_buffer_mapping_.get());
+  return GetSensorReadingFromBuffer(buffer, result);
+}
+
 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)
@@ skipping 30 matching lines @@
 
   if (!optimal_configuration) {
     StopSensor();
     return true;
   }
 
   return StartSensor(*optimal_configuration);
 }
 
 }  // namespace device