Remove unnecessary Document.h includes in .cpp files

Source/core/page/DragData.cpp

 /*
  * Copyright (C) 2007 Apple Inc.  All rights reserved.
  * Copyright (C) 2013 Google Inc.
  *
  * 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
@@ skipping 10 matching lines @@
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 #include "core/page/DragData.h"
 
 #include "core/clipboard/DataObject.h"
-#include "core/dom/Document.h"
 #include "core/dom/DocumentFragment.h"
 #include "core/dom/Range.h"
 #include "core/editing/markup.h"
 #include "core/frame/LocalFrame.h"
 #include "platform/FileMetadata.h"
 #include "platform/clipboard/ClipboardMimeTypes.h"
 #include "platform/weborigin/KURL.h"
 #include "wtf/text/WTFString.h"
 
 namespace WebCore {
@@ skipping 117 matching lines @@
 
     return nullptr;
 }
 
 String DragData::droppedFileSystemId() const
 {
     return m_platformDragData->filesystemId();
 }
 
 } // namespace WebCore