Enable selection for the composed tree

Source/core/layout/LayoutView.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 786 matching lines @@
     LayoutObject* startLayoutObject = startPos.anchorNode()->layoutObject();
     LayoutObject* endLayoutObject = endPos.anchorNode()->layoutObject();
     if (!startLayoutObject || !endLayoutObject)
         return;
     ASSERT(startLayoutObject->view() == this && endLayoutObject->view() == this);
     setSelection(startLayoutObject, startPos.deprecatedEditingOffset(), endLayoutObject, endPos.deprecatedEditingOffset());
 }
 
 void LayoutView::commitPendingSelection()
 {
+    if (RuntimeEnabledFeatures::selectionForComposedTreeEnabled())
+        return commitPendingSelectionAlgorithm<VisibleSelection::InComposedTree>();
     commitPendingSelectionAlgorithm<VisibleSelection::InDOMTree>();
 }
 
 LayoutObject* LayoutView::selectionStart()
 {
     commitPendingSelection();
     return m_selectionStart;
 }
 
 LayoutObject* LayoutView::selectionEnd()
@@ skipping 153 matching lines @@
     return viewHeight(IncludeScrollbars) / scale;
 }
 
 void LayoutView::willBeDestroyed()
 {
     LayoutBlockFlow::willBeDestroyed();
     m_compositor.clear();
 }
 
 } // namespace blink