Clean up forward declarations in Source/core/html

Source/core/html/shadow/DateTimeEditElement.h

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
@@ skipping 16 matching lines @@
 #define DateTimeEditElement_h
 
 #if ENABLE(INPUT_MULTIPLE_FIELDS_UI)
 #include "core/html/forms/StepRange.h"
 #include "core/html/shadow/DateTimeFieldElement.h"
 #include "platform/DateComponents.h"
 
 namespace blink {
 
 class DateTimeFieldsState;
-class KeyboardEvent;
 class Locale;
-class MouseEvent;
 class StepRange;
 
 // DateTimeEditElement class contains numberic field and symbolc field for
 // representing date and time, such as
 //  - Year, Month, Day Of Month
 //  - Hour, Minute, Second, Millisecond, AM/PM
 class DateTimeEditElement FINAL : public HTMLDivElement, public DateTimeFieldElement::FieldOwner {
     WTF_MAKE_NONCOPYABLE(DateTimeEditElement);
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(DateTimeEditElement);
 
@@ skipping 103 matching lines @@
     WillBeHeapVector<RawPtrWillBeMember<DateTimeFieldElement>, maximumNumberOfFields> m_fields;
     RawPtrWillBeMember<EditControlOwner> m_editControlOwner;
 };
 
 DEFINE_TYPE_CASTS(DateTimeEditElement, Element, element, element->isDateTimeEditElement(), element.isDateTimeEditElement());
 
 } // namespace blink
 
 #endif
 #endif