Make static KURLs thread safe

third_party/WebKit/Source/core/html/HTMLImageElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 106 matching lines @@
 
   // CanvasImageSource implementation
   PassRefPtr<Image> getSourceImageForCanvas(SourceImageStatus*,
                                             AccelerationHint,
                                             SnapshotReason,
                                             const FloatSize&) const override;
   bool isSVGSource() const override;
   bool wouldTaintOrigin(SecurityOrigin*) const override;
   FloatSize elementSize(const FloatSize&) const override;
   FloatSize defaultDestinationSize(const FloatSize&) const override;
-  const KURL& sourceURL() const override;
+  KURL sourceURL() const override;
   bool isAccelerated() const override { return false; }
   bool isOpaque() const override;
   int sourceWidth() override;
   int sourceHeight() override;
 
   // public so that HTMLPictureElement can call this as well.
   void selectSourceURL(ImageLoader::UpdateFromElementBehavior);
 
   void setIsFallbackImage() { m_isFallbackImage = true; }
 
@@ skipping 84 matching lines @@
   unsigned m_formWasSetByParser : 1;
   unsigned m_elementCreatedByParser : 1;
   unsigned m_isFallbackImage : 1;
 
   ReferrerPolicy m_referrerPolicy;
 };
 
 }  // namespace blink
 
 #endif  // HTMLImageElement_h