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

third_party/WebKit/Source/core/html/HTMLMediaElementTest.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/html/HTMLMediaElement.h"
 
 #include "core/frame/Settings.h"
 #include "core/html/HTMLAudioElement.h"
 #include "core/html/HTMLVideoElement.h"
 #include "core/page/NetworkStateNotifier.h"
@@ skipping 69 matching lines @@
       return "ftp://example.com/foo.mp4";
     case TestURLScheme::kFile:
       return "file:///foo/bar.mp4";
     case TestURLScheme::kData:
       return "data:video/mp4;base64,XXXXXXX";
     case TestURLScheme::kBlob:
       return "blob:http://example.com/00000000-0000-0000-0000-000000000000";
     default:
       NOTREACHED();
   }
-  return emptyString();
+  return emptyString;
 }
 
 TEST_P(HTMLMediaElementTest, preloadType) {
   struct TestData {
     bool dataSaverEnabled;
     bool forcePreloadNoneForMediaElements;
     bool isCellular;
     TestURLScheme srcScheme;
     AtomicString preloadToSet;
     AtomicString preloadExpected;
@@ skipping 31 matching lines @@
     setCurrentSrc(srcSchemeToURL(data.srcScheme));
     media()->setPreload(data.preloadToSet);
 
     EXPECT_EQ(data.preloadExpected, media()->preload())
         << "preload type differs at index" << index;
     ++index;
   }
 }
 
 }  // namespace blink