Document the tracking bugs of some IDL FIXMEs and TODOs

Source/core/svg/SVGElement.idl

 /*
  * Copyright (C) 2004, 2005 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005 Rob Buis <buis@kde.org>
  * Copyright (C) 2006 Samuel Weinig <sam.weinig@gmail.com>
  * Copyright (C) 2006 Apple 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 11 matching lines @@
 
 // http://www.w3.org/TR/SVG2/types.html#InterfaceSVGElement
 
 interface SVGElement : Element {
     [RuntimeEnabled=SVG1DOM, MeasureAs=SVGClassName] readonly attribute SVGAnimatedString className;
     readonly attribute CSSStyleDeclaration style;
 
     readonly attribute SVGSVGElement? ownerSVGElement;
     readonly attribute SVGElement? viewportElement;
     [CustomElementCallbacks] attribute long tabIndex;
-    // TODO(philipj): focus() and blur() are on Element.
+    // TODO(philipj): focus() and blur() are on Element. crbug.com/497274
 };
 
 SVGElement implements GlobalEventHandlers;