[Sensors] Fix reading updates after page refresh

third_party/WebKit/Source/modules/sensor/SensorReadingUpdater.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 SensorReadingUpdater_h
 #define SensorReadingUpdater_h
 
 #include "device/generic_sensor/public/interfaces/sensor_provider.mojom-blink.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
+class Document;
 class SensorProxy;
 
 // This class encapsulates sensor reading update notification logic.
 class SensorReadingUpdater : public GarbageCollected<SensorReadingUpdater> {
  public:
   static SensorReadingUpdater* create(SensorProxy*,
                                       device::mojom::blink::ReportingMode);
 
   virtual void start();
 
   DECLARE_VIRTUAL_TRACE();
 
  protected:
   explicit SensorReadingUpdater(SensorProxy*);
   void enqueueAnimationFrameTask();
   virtual void onAnimationFrameInternal() = 0;
 
   Member<SensorProxy> m_sensorProxy;
+  WeakMember<Document> m_document;
   bool m_hasPendingAnimationFrameTask;
 
  private:
   void onAnimationFrame();
 };
 
 }  // namespace blink
 
 #endif  // SensorReadingUpdater_h