Replace WTF::emptyString{16Bit}() with a static global

third_party/WebKit/Source/core/frame/LocalFrame.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Simon Hausmann <hausmann@kde.org>
  *                     2000 Stefan Schimanski <1Stein@gmx.de>
  *                     2001 George Staikos <staikos@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2005 Alexey Proskuryakov <ap@nypop.com>
@@ skipping 728 matching lines @@
                         enclosingIntRect(paintingRect));
   return dragImageBuilder.createImage(opacity);
 }
 
 String LocalFrame::selectedText() const {
   return selection().selectedText();
 }
 
 String LocalFrame::selectedTextForClipboard() const {
   if (!document())
-    return emptyString();
+    return emptyString;
   DCHECK(!document()->needsLayoutTreeUpdate());
   return selection().selectedTextForClipboard();
 }
 
 PositionWithAffinity LocalFrame::positionForPoint(const IntPoint& framePoint) {
   HitTestResult result = eventHandler().hitTestResultAtPoint(framePoint);
   Node* node = result.innerNodeOrImageMapImage();
   if (!node)
     return PositionWithAffinity();
   LayoutObject* layoutObject = node->layoutObject();
@@ skipping 178 matching lines @@
   if (m_frame && m_frame->client() && m_frame->client()->frameBlameContext())
     m_frame->client()->frameBlameContext()->Enter();
 }
 
 ScopedFrameBlamer::~ScopedFrameBlamer() {
   if (m_frame && m_frame->client() && m_frame->client()->frameBlameContext())
     m_frame->client()->frameBlameContext()->Leave();
 }
 
 }  // namespace blink