Get rid of unused member function rootEditableElement() in...

Get rid of unused member function rootEditableElement() in PositionAlgorithm<Strategy> template class

This patch gets rid of unused member function |rootEditableElement()| in
|PositionAlgorithm<Strategy>| template class to simplify source code for
improving code health.

BUG=518738
TEST=n/a; no behavior changes

Review URL: https://codereview.chromium.org/1303673002

git-svn-id: svn://svn.chromium.org/blink/trunk@200805 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/editing/Position.h

@@ -160,11 +160,6 @@ public:
 
     Document* document() const { return m_anchorNode ? &m_anchorNode->document() : 0; }
     bool inDocument() const { return m_anchorNode && m_anchorNode->inDocument(); }
-    Element* rootEditableElement() const
-    {
-        Node* container = computeContainerNode();
-        return container ? container->rootEditableElement() : 0;
-    }
 
     bool isNull() const { return !m_anchorNode; }
     bool isNotNull() const { return m_anchorNode; }