Move global function lowestEditableAncestor() to local function in VisibleSelection.cpp

Source/core/editing/VisibleSelection.cpp

 /*
  * Copyright (C) 2004, 2005, 2006 Apple Computer, 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 887 matching lines @@
         m_startInComposedTree = adjustPositionInComposedTreeForStart(m_startInComposedTree, shadowHost);
         m_extentInComposedTree = m_startInComposedTree;
     }
 }
 
 bool VisibleSelection::isBaseFirstInComposedTree() const
 {
     return m_baseInComposedTree.isNotNull() && m_baseInComposedTree.compareTo(m_extentInComposedTree) <= 0;
 }
 
+static Element* lowestEditableAncestor(Node* node)
+{
+    while (node) {
+        if (node->hasEditableStyle())
+            return node->rootEditableElement();
+        if (isHTMLBodyElement(*node))
+            break;
+        node = node->parentNode();
+    }
+
+    return nullptr;
+}
+
 void VisibleSelection::adjustSelectionToAvoidCrossingEditingBoundaries()
 {
     if (m_base.isNull() || m_start.isNull() || m_end.isNull())
         return;
 
     ContainerNode* baseRoot = highestEditableRoot(m_base);
     ContainerNode* startRoot = highestEditableRoot(m_start);
     ContainerNode* endRoot = highestEditableRoot(m_end);
 
     Element* baseEditableAncestor = lowestEditableAncestor(m_base.computeContainerNode());
@@ skipping 326 matching lines @@
     sel.showTreeForThis();
 }
 
 void showTree(const blink::VisibleSelection* sel)
 {
     if (sel)
         sel->showTreeForThis();
 }
 
 #endif