Use a ThreadChecker in DeviceSensorHost instead of DCHECK_CURRENTLY_ON.

content/browser/device_sensors/device_sensor_host.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 CONTENT_BROWSER_DEVICE_SENSORS_DEVICE_SENSOR_HOST_H_
 #define CONTENT_BROWSER_DEVICE_SENSORS_DEVICE_SENSOR_HOST_H_
 
 #include "base/macros.h"
 #include "base/memory/shared_memory.h"
 #include "content/browser/device_sensors/device_sensors_consts.h"
@@ skipping 18 matching lines @@
   explicit DeviceSensorHost(mojo::InterfaceRequest<MojoInterface> request);
 
   void StartPolling(
       const typename MojoInterface::StartPollingCallback& callback) override;
   void StopPolling() override;
 
   bool is_started_;
 
   mojo::StrongBinding<MojoInterface> binding_;
 
+  base::ThreadChecker thread_checker_;
+
   DISALLOW_COPY_AND_ASSIGN(DeviceSensorHost);
 };
 
 using DeviceLightHost =
     DeviceSensorHost<device::mojom::LightSensor, CONSUMER_TYPE_LIGHT>;
 using DeviceMotionHost =
     DeviceSensorHost<device::mojom::MotionSensor, CONSUMER_TYPE_MOTION>;
 using DeviceOrientationHost = DeviceSensorHost<device::mojom::OrientationSensor,
                                                CONSUMER_TYPE_ORIENTATION>;
 using DeviceOrientationAbsoluteHost =
     DeviceSensorHost<device::mojom::OrientationAbsoluteSensor,
                      CONSUMER_TYPE_ORIENTATION_ABSOLUTE>;
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DEVICE_SENSORS_DEVICE_SENSOR_HOST_H_