mshtml: Add IHTMLXMLHttpRequest::responseXML() method implementation.

[Nikolay Sivov]

On 04.11.2015 11:13, Zhenbo Li wrote:
> +    hres = IXMLDOMDocument_loadXML(xmldoc, str, &vbool);
> +    if(FAILED(hres)) {
> +        ERR("loadXML(%s) failed: %08x\n", debugstr_w(str), hres);
> +        IXMLDOMDocument_Release(xmldoc);
> +        SysFreeString(str);
> +        return hres;
> +    }

This is not how it works. loadXML() returns S_FALSE on load failure as 
well, so you have to test strictly for S_OK, or check VARIANT_BOOL 
argument. You can probably add a test when invalid xml stream is 
received to see how _get_responseXML() behaves, e.g. does it return 
S_FALSE and a valid IDispatch or does it fail and return NULL.

Also I don't think it's a good idea to trace xml contents.