Move a static member function nodeIsUserSelectNone() out from PositionAlgorithm template class

Source/core/editing/SelectionController.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2012 Digia Plc. and/or its subsidiary(-ies)
  * 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
@@ skipping 265 matching lines @@
 
     if (selection().granularity() != CharacterGranularity)
         expandSelectionUsingGranularity(newSelection, selection().granularity());
 
     selection().setNonDirectionalSelectionIfNeeded(newSelection, selection().granularity(),
         FrameSelection::AdjustEndpointsAtBidiBoundary);
 }
 
 bool SelectionController::updateSelectionForMouseDownDispatchingSelectStart(Node* targetNode, const VisibleSelection& selection, TextGranularity granularity)
 {
-    if (Position::nodeIsUserSelectNone(targetNode))
+    if (nodeIsUserSelectNone(targetNode))
         return false;
 
     if (!dispatchSelectStart(targetNode))
         return false;
 
     if (!selection.isValidFor(*m_frame->document()))
         return false;
 
     if (selection.isRange()) {
         m_selectionState = SelectionState::ExtendedSelection;
@@ skipping 352 matching lines @@
     else
         m_selectionState = SelectionState::HaveNotStartedSelection;
 }
 
 FrameSelection& SelectionController::selection() const
 {
     return m_frame->selection();
 }
 
 } // namespace blink