Make static KURLs thread safe

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 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
@@ skipping 802 matching lines @@
   //
   // Instead of dealing with that, there's a separate check that the
   // ImageResourceContent has non-null image data associated with it, which
   // isn't folded into imageHasLoaded above.
   if ((imageHasLoaded && imageHasImage) || imageStillLoading || imageIsDocument)
     ensurePrimaryContent();
   else
     ensureCollapsedOrFallbackContent();
 }
 
-const KURL& HTMLImageElement::sourceURL() const {
+KURL HTMLImageElement::sourceURL() const {
   return cachedImage()->response().url();
 }
 
 void HTMLImageElement::didAddUserAgentShadowRoot(ShadowRoot&) {
   HTMLImageFallbackHelper::createAltTextShadowTree(*this);
 }
 
 void HTMLImageElement::ensureFallbackForGeneratedContent() {
   // The special casing for generated content in createLayoutObject breaks the
   // invariant that the layout object attached to this element will always be
@@ skipping 87 matching lines @@
 void HTMLImageElement::associateWith(HTMLFormElement* form) {
   if (form && form->isConnected()) {
     m_form = form;
     m_formWasSetByParser = true;
     m_form->associate(*this);
     m_form->didAssociateByParser();
   }
 };
 
 }  // namespace blink