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

third_party/WebKit/Source/wtf/text/StringBuilder.cpp

 /*
  * Copyright (C) 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2012 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:
  * 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
@@ skipping 17 matching lines @@
 
 #include "wtf/dtoa.h"
 #include "wtf/text/IntegerToStringConversion.h"
 #include "wtf/text/WTFString.h"
 #include <algorithm>
 
 namespace WTF {
 
 String StringBuilder::toString() {
   if (!m_length)
-    return emptyString();
+    return emptyString;
   if (m_string.isNull()) {
     if (m_is8Bit)
       m_string = String(characters8(), m_length);
     else
       m_string = String(characters16(), m_length);
     clearBuffer();
   }
   return m_string;
 }
 
 AtomicString StringBuilder::toAtomicString() {
   if (!m_length)
     return emptyAtom;
   if (m_string.isNull()) {
     if (m_is8Bit)
       m_string = AtomicString(characters8(), m_length);
     else
       m_string = AtomicString(characters16(), m_length);
     clearBuffer();
   }
   return AtomicString(m_string);
 }
 
 String StringBuilder::substring(unsigned start, unsigned length) const {
   if (start >= m_length)
-    return emptyString();
+    return emptyString;
   if (!m_string.isNull())
     return m_string.substring(start, length);
   length = std::min(length, m_length - start);
   if (m_is8Bit)
     return String(characters8() + start, length);
   return String(characters16() + start, length);
 }
 
 void StringBuilder::swap(StringBuilder& builder) {
   std::swap(m_string, builder.m_string);
@@ skipping 149 matching lines @@
 void StringBuilder::appendNumber(unsigned long long number) {
   appendIntegerInternal(*this, number);
 }
 
 void StringBuilder::appendNumber(double number, unsigned precision) {
   NumberToStringBuffer buffer;
   append(numberToFixedPrecisionString(number, precision, buffer));
 }
 
 }  // namespace WTF