Let Selection.collapse remember a raw Position instead of a canonicalized one.

Source/core/page/DOMSelection.cpp

 /*
  * Copyright (C) 2007, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2012 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.
@@ skipping 189 matching lines @@
     if (!m_frame)
         return;
 
     if (offset < 0) {
         exceptionState.throwDOMException(IndexSizeError, String::number(offset) + " is not a valid offset.");
         return;
     }
 
     if (!isValidForPosition(node))
         return;
-
-    // FIXME: Eliminate legacy editing positions
-    m_frame->selection().moveTo(VisiblePosition(createLegacyEditingPosition(node, offset), DOWNSTREAM));
+    RefPtrWillBeRawPtr<Range> range = Range::create(node->document());
+    range->setStart(node, offset, exceptionState);
+    if (exceptionState.hadException())
+        return;
+    range->setEnd(node, offset, exceptionState);
+    if (exceptionState.hadException())
+        return;
+    m_frame->selection().setSelectedRange(range.get(), DOWNSTREAM, m_frame->selection().isDirectional());
 }
 
 void DOMSelection::collapse(Node* node, ExceptionState& exceptionState)
 {
     collapse(node, 0, exceptionState);
 }
 
 void DOMSelection::collapseToEnd(ExceptionState& exceptionState)
 {
     if (!m_frame)
@@ skipping 327 matching lines @@
     return node->document() == m_frame->document();
 }
 
 void DOMSelection::addConsoleError(const String& message)
 {
     if (m_treeScope)
         m_treeScope->document().addConsoleMessage(JSMessageSource, ErrorMessageLevel, message);
 }
 
 } // namespace WebCore