Make Position::FirstPositionInNode() to take const Node& instead of Node*

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

 /*
  * Copyright (C) 2004, 2006, 2008 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 175 matching lines @@
   bool AtLastEditingPositionForNode() const;
 
   bool AtStartOfTree() const;
   bool AtEndOfTree() const;
 
   static PositionTemplate<Strategy> BeforeNode(const Node& anchor_node);
   static PositionTemplate<Strategy> AfterNode(const Node& anchor_node);
   static PositionTemplate<Strategy> InParentBeforeNode(const Node& anchor_node);
   static PositionTemplate<Strategy> InParentAfterNode(const Node& anchor_node);
   static int LastOffsetInNode(Node* anchor_node);
-  static PositionTemplate<Strategy> FirstPositionInNode(Node* anchor_node);
+  static PositionTemplate<Strategy> FirstPositionInNode(
+      const Node& anchor_node);
   static PositionTemplate<Strategy> LastPositionInNode(Node* anchor_node);
   static PositionTemplate<Strategy> FirstPositionInOrBeforeNode(
       Node* anchor_node);
   static PositionTemplate<Strategy> LastPositionInOrAfterNode(
       Node* anchor_node);
 
   String ToAnchorTypeAndOffsetString() const;
 #ifndef NDEBUG
   void ShowTreeForThis() const;
   void ShowTreeForThisInFlatTree() const;
@@ skipping 76 matching lines @@
 
 }  // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showTree(const blink::Position&);
 void showTree(const blink::Position*);
 #endif
 
 #endif  // Position_h