[Sensors] Align sensor reading attribute implementation with the specification

third_party/WebKit/Source/modules/sensor/SensorReadingEvent.cpp

-// 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 "modules/sensor/SensorReadingEvent.h"
-
-namespace blink {
-
-SensorReadingEvent::~SensorReadingEvent() = default;
-
-SensorReadingEvent::SensorReadingEvent(const AtomicString& eventType,
-                                       SensorReading* reading)
-    : Event(eventType, false, false),  // Does not bubble and is not cancelable.
-      m_reading(reading) {
-  DCHECK(m_reading);
-}
-
-SensorReadingEvent::SensorReadingEvent(
-    const AtomicString& eventType,
-    const SensorReadingEventInit& initializer)
-    : SensorReadingEvent(eventType, initializer.reading()) {}
-
-const AtomicString& SensorReadingEvent::interfaceName() const {
-  return EventNames::SensorReadingEvent;
-}
-
-DEFINE_TRACE(SensorReadingEvent) {
-  Event::trace(visitor);
-  visitor->trace(m_reading);
-}
-
-}  // namespace blink