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

third_party/WebKit/Source/core/style/QuotesData.cpp

Index: third_party/WebKit/Source/core/style/QuotesData.cpp
diff --git a/third_party/WebKit/Source/core/style/QuotesData.cpp b/third_party/WebKit/Source/core/style/QuotesData.cpp
index 5b088c6db553fcacf9d29ef962ccd3863a9dd46a..0eafa382c163ffbe1b7b67aa0dff2cea68e2ada7 100644
--- a/third_party/WebKit/Source/core/style/QuotesData.cpp
+++ b/third_party/WebKit/Source/core/style/QuotesData.cpp
@@ -40,7 +40,7 @@ void QuotesData::addPair(std::pair<String, String> quotePair) {
 const String QuotesData::getOpenQuote(int index) const {
   ASSERT(index >= 0);
   if (!m_quotePairs.size() || index < 0)
-    return emptyString();
+    return emptyString;
   if ((size_t)index >= m_quotePairs.size())
     return m_quotePairs.back().first;
   return m_quotePairs.at(index).first;
@@ -49,7 +49,7 @@ const String QuotesData::getOpenQuote(int index) const {
 const String QuotesData::getCloseQuote(int index) const {
   ASSERT(index >= -1);
   if (!m_quotePairs.size() || index < 0)
-    return emptyString();
+    return emptyString;
   if ((size_t)index >= m_quotePairs.size())
     return m_quotePairs.back().second;
   return m_quotePairs.at(index).second;