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

third_party/WebKit/Source/modules/webmidi/MIDIPort.cpp

 /*
  * Copyright (C) 2013 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 51 matching lines @@
 
 String MIDIPort::connection() const {
   switch (m_connection) {
     case ConnectionStateOpen:
       return "open";
     case ConnectionStateClosed:
       return "closed";
     case ConnectionStatePending:
       return "pending";
   }
-  return emptyString();
+  return emptyString;
 }
 
 String MIDIPort::state() const {
   switch (m_state) {
     case PortState::DISCONNECTED:
       return "disconnected";
     case PortState::CONNECTED:
       return "connected";
     case PortState::OPENED:
       NOTREACHED();
       return "connected";
   }
-  return emptyString();
+  return emptyString;
 }
 
 String MIDIPort::type() const {
   switch (m_type) {
     case TypeInput:
       return "input";
     case TypeOutput:
       return "output";
   }
-  return emptyString();
+  return emptyString;
 }
 
 ScriptPromise MIDIPort::open(ScriptState* scriptState) {
   open();
   return accept(scriptState);
 }
 
 ScriptPromise MIDIPort::close(ScriptState* scriptState) {
   if (m_connection != ConnectionStateClosed) {
     // TODO(toyoshim): Do clear() operation on MIDIOutput.
@@ skipping 98 matching lines @@
   DCHECK(state != PortState::DISCONNECTED || connection != ConnectionStateOpen);
   if (m_state == state && m_connection == connection)
     return;
   m_state = state;
   m_connection = connection;
   dispatchEvent(MIDIConnectionEvent::create(this));
   m_access->dispatchEvent(MIDIConnectionEvent::create(this));
 }
 
 }  // namespace blink