Returning const by ref instead of const by value in ApplyBlockElementCommand::tagName() api

Source/core/editing/commands/ApplyBlockElementCommand.h

 /*
  * Copyright (C) 2010 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 25 matching lines @@
 
 namespace blink {
 
 class ApplyBlockElementCommand : public CompositeEditCommand {
 protected:
     ApplyBlockElementCommand(Document&, const QualifiedName& tagName, const AtomicString& inlineStyle);
     ApplyBlockElementCommand(Document&, const QualifiedName& tagName);
 
     virtual void formatSelection(const VisiblePosition& startOfSelection, const VisiblePosition& endOfSelection);
     PassRefPtrWillBeRawPtr<HTMLElement> createBlockElement() const;
-    const QualifiedName tagName() const { return m_tagName; }
+    const QualifiedName& tagName() const { return m_tagName; }
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     void doApply() final;
     virtual void formatRange(const Position& start, const Position& end, const Position& endOfSelection, RefPtrWillBeRawPtr<HTMLElement>&) = 0;
     void rangeForParagraphSplittingTextNodesIfNeeded(const VisiblePosition&, Position&, Position&);
     VisiblePosition endOfNextParagrahSplittingTextNodesIfNeeded(VisiblePosition&, Position&, Position&);
 
     QualifiedName m_tagName;
     AtomicString m_inlineStyle;
     Position m_endOfLastParagraph;
 };
 
 }
 
 #endif