Make static KURLs thread safe

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

 /*
  * Copyright (C) 2007, 2008, 2009, 2010 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 86 matching lines @@
   KURL posterImageURL() const override;
 
   // CanvasImageSource implementation
   PassRefPtr<Image> getSourceImageForCanvas(SourceImageStatus*,
                                             AccelerationHint,
                                             SnapshotReason,
                                             const FloatSize&) const override;
   bool isVideoElement() const override { return true; }
   bool wouldTaintOrigin(SecurityOrigin*) const override;
   FloatSize elementSize(const FloatSize&) const override;
-  const KURL& sourceURL() const override { return currentSrc(); }
+  KURL sourceURL() const override { return currentSrc(); }
   bool isHTMLVideoElement() const override { return true; }
   int sourceWidth() override { return videoWidth(); }
   int sourceHeight() override { return videoHeight(); }
   // Video elements currently always go through RAM when used as a canvas image
   // source.
   bool isAccelerated() const override { return false; }
 
   // ImageBitmapSource implementation
   IntSize bitmapSourceSize() const override;
   ScriptPromise createImageBitmap(ScriptState*,
@@ skipping 21 matching lines @@
   void setDisplayMode(DisplayMode) override;
 
   Member<HTMLImageLoader> m_imageLoader;
 
   AtomicString m_defaultPosterURL;
 };
 
 }  // namespace blink
 
 #endif  // HTMLVideoElement_h