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

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

 /*
  * Copyright (C) 2004, 2005, 2006, 2009 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 582 matching lines @@
     case PositionAnchorType::BeforeChildren:
       return "beforeChildren";
     case PositionAnchorType::AfterChildren:
       return "afterChildren";
     case PositionAnchorType::BeforeAnchor:
       return "beforeAnchor";
     case PositionAnchorType::AfterAnchor:
       return "afterAnchor";
   }
   NOTREACHED();
-  return emptyString();
+  return emptyString;
 }
 
 #ifndef NDEBUG
 
 template <typename Strategy>
 void PositionTemplate<Strategy>::showTreeForThis() const {
   if (!anchorNode())
     return;
   LOG(INFO) << "\n"
             << anchorNode()->toTreeStringForThis().utf8().data()
@@ skipping 58 matching lines @@
 }
 
 void showTree(const blink::Position* pos) {
   if (pos)
     pos->showTreeForThis();
   else
     LOG(INFO) << "Cannot showTree for <null>";
 }
 
 #endif