Remove DeviceLightEvent implementation

third_party/WebKit/Source/modules/device_light/DeviceLightDispatcher.h

-// Copyright 2014 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 DeviceLightDispatcher_h
-#define DeviceLightDispatcher_h
-
-#include "core/frame/PlatformEventDispatcher.h"
-#include "platform/heap/Handle.h"
-#include "public/platform/WebDeviceLightListener.h"
-
-namespace blink {
-
-// This class listens to device light data and notifies all registered
-// controllers.
-class DeviceLightDispatcher final
-    : public GarbageCollectedFinalized<DeviceLightDispatcher>,
-      public PlatformEventDispatcher,
-      public WebDeviceLightListener {
-  USING_GARBAGE_COLLECTED_MIXIN(DeviceLightDispatcher);
-
- public:
-  static DeviceLightDispatcher& Instance();
-  ~DeviceLightDispatcher() override;
-
-  double LatestDeviceLightData() const;
-
-  // Inherited from WebDeviceLightListener.
-  void DidChangeDeviceLight(double) override;
-
-  DECLARE_VIRTUAL_TRACE();
-
- private:
-  DeviceLightDispatcher();
-
-  // Inherited from PlatformEventDispatcher.
-  void StartListening() override;
-  void StopListening() override;
-
-  double last_device_light_data_;
-};
-
-}  // namespace blink
-
-#endif  // DeviceLightDispatcher_h