Templatize extractSelectedText used by FrameSelection function

Source/core/editing/FrameSelection.cpp

 /*
  * Copyright (C) 2004, 2008, 2009, 2010 Apple 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 1645 matching lines @@
             }
             target = target->parentOrShadowHostElement();
         }
         m_frame->document()->setFocusedElement(nullptr);
     }
 
     if (caretBrowsing)
         m_frame->page()->focusController().setFocusedElement(0, m_frame);
 }
 
+template <typename Strategy>
+String extractSelectedTextAlgorithm(const FrameSelection& selection, TextIteratorBehavior behavior)
+{
+    using PositionType = typename Strategy::PositionType;
+
+    PositionType start;
+    PositionType end;
+    VisibleSelection visibleSelection = selection.selection();
+    VisibleSelection::normalizePositions(Strategy::selectionStart(visibleSelection), Strategy::selectionEnd(visibleSelection), &start, &end);
+    // We remove '\0' characters because they are not visibly rendered to the user.
+    return plainText(start, end, behavior).replace(0, "");
+}
+
 static String extractSelectedText(const FrameSelection& selection, TextIteratorBehavior behavior)
 {
-    // We remove '\0' characters because they are not visibly rendered to the user.
-    return plainText(selection.toNormalizedRange().get(), behavior).replace(0, "");
+    return extractSelectedTextAlgorithm<VisibleSelection::InDOMTree>(selection, behavior);
 }
 
 String FrameSelection::selectedHTMLForClipboard() const
 {
     return createMarkup(m_selection.toNormalizedRange().get(), AnnotateForInterchange, ConvertBlocksToInlines::NotConvert, ResolveNonLocalURLs);
 }
 
 String FrameSelection::selectedText() const
 {
     return extractSelectedText(*this, TextIteratorDefaultBehavior);
@@ skipping 293 matching lines @@
 
 void showTree(const blink::FrameSelection* sel)
 {
     if (sel)
         sel->showTreeForThis();
     else
         fprintf(stderr, "Cannot showTree for (nil) FrameSelection.\n");
 }
 
 #endif