We don't need to directly build SVGURIReference in V8 - these properties are only accessed by inheritance; it used to be harmless but recent changes cause it to fail in compile.
Created attachment 40881 [details] patch
To be more specific, the fix is to not generate and compile in code directly from SVGURIReference.idl. The interface therein should only be used through derived classes.
Comment on attachment 40881 [details] patch Tab in ChangeLog will cause commit to fail. Normally I don't put anything around urls, the [] seem superfluous to me. LGTM.
Created attachment 40882 [details] better patch
Created attachment 40906 [details] patch part 2 A second patch is required to fix this problem, as the .h file is still referenced.
Comment on attachment 40906 [details] patch part 2 r=me.
Comment on attachment 40882 [details] better patch already applied.
Landed as r49319