Replace forward class declarations of VisibleSelection to include directive

Source/core/editing/SelectionController.h

 /*
  * Copyright (C) 2006, 2007, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2015 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
@@ skipping 11 matching lines @@
  * 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.
  */
 
 #ifndef SelectionController_h
 #define SelectionController_h
 
 #include "core/CoreExport.h"
 #include "core/editing/TextGranularity.h"
+#include "core/editing/VisibleSelection.h"
 #include "core/page/EventWithHitTestResults.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 class FrameSelection;
 class HitTestResult;
 class LocalFrame;
-class VisibleSelection;
 
 class SelectionController final : public NoBaseWillBeGarbageCollected<SelectionController> {
     WTF_MAKE_NONCOPYABLE(SelectionController);
     WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED(SelectionController);
 public:
     static PassOwnPtrWillBeRawPtr<SelectionController> create(LocalFrame&);
     DECLARE_TRACE();
 
     bool updateSelectionForMouseDownDispatchingSelectStart(Node*, const VisibleSelection&, TextGranularity);
     void handleMousePressEvent(const MouseEventWithHitTestResults&);
@@ skipping 36 matching lines @@
 
     RawPtrWillBeMember<LocalFrame> const m_frame;
     bool m_mouseDownMayStartSelect;
     bool m_mouseDownWasSingleClickInSelection;
     enum class SelectionState { HaveNotStartedSelection, PlacedCaret, ExtendedSelection };
     SelectionState m_selectionState;
 };
 
 } // namespace blink
 #endif // SelectionController_h