Oilpan: fix build after r202130.

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 1981 matching lines @@
 void FrameSelection::showTreeForThis() const
 {
     selection().showTreeForThis();
 }
 
 #endif
 
 DEFINE_TRACE(FrameSelection)
 {
     visitor->trace(m_frame);
-    visitor->trace(selection());
+    visitor->trace(m_selection);
     visitor->trace(m_originalBase);
     visitor->trace(m_logicalRange);
     visitor->trace(m_previousCaretNode);
     visitor->trace(m_typingStyle);
     VisibleSelectionChangeObserver::trace(visitor);
 }
 
 void FrameSelection::setCaretRectNeedsUpdate()
 {
     m_caretRectDirty = true;
@@ skipping 80 matching lines @@
 
 void showTree(const blink::FrameSelection* sel)
 {
     if (sel)
         sel->showTreeForThis();
     else
         fprintf(stderr, "Cannot showTree for (nil) FrameSelection.\n");
 }
 
 #endif