Templatize extractSelectedText used by FrameSelection function

Source/core/editing/FrameSelection.cpp

Index: Source/core/editing/FrameSelection.cpp
diff --git a/Source/core/editing/FrameSelection.cpp b/Source/core/editing/FrameSelection.cpp
index bdba0152fa4165f0b667948ef790bd507d0333b4..0c9e2192c4d59bce29b6fee775e41a93f43daf69 100644
--- a/Source/core/editing/FrameSelection.cpp
+++ b/Source/core/editing/FrameSelection.cpp
@@ -1663,10 +1663,22 @@ void FrameSelection::setFocusedNodeIfNeeded()
         m_frame->page()->focusController().setFocusedElement(0, m_frame);
 }
 
-static String extractSelectedText(const FrameSelection& selection, TextIteratorBehavior behavior)
+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(selection.toNormalizedRange().get(), behavior).replace(0, "");
+    return plainText(start, end, behavior).replace(0, "");
+}
+
+static String extractSelectedText(const FrameSelection& selection, TextIteratorBehavior behavior)
+{
+    return extractSelectedTextAlgorithm<VisibleSelection::InDOMTree>(selection, behavior);
 }
 
 String FrameSelection::selectedHTMLForClipboard() const