Clean up forward declarations in Source/modules

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"
-#include "wtf/RefPtr.h"
 
 namespace blink {
 
-class DeviceLightController;
-
 // 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();
     virtual ~DeviceLightDispatcher();
 
     double latestDeviceLightData() const;
 
     // Inherited from WebDeviceLightListener.
     virtual void didChangeDeviceLight(double) override;
 
     virtual void trace(Visitor*) override;
 
 private:
     DeviceLightDispatcher();
 
     // Inherited from PlatformEventDispatcher.
     virtual void startListening() override;
     virtual void stopListening() override;
 
     double m_lastDeviceLightData;
 };
 
 } // namespace blink
 
 #endif // DeviceLightDispatcher_h