IHTMLWindow2からのIAccessible取り出し

hoge.cpp

#define UNICODE
#include <windows.h>
#include <Shlwapi.h>
#include <oleacc.h>
#include <Exdisp.h>
#import <shdocvw.dll>
#import <mshtml.tlb>

#define URL L"https://www.google.co.jp/?gws_rd=ssl"
_COM_SMARTPTR_TYPEDEF(IAccessible, __uuidof(IAccessible));

HRESULT test()
{
	HRESULT hr = S_OK;
	try{

		SHDocVw::IShellWindowsPtr psw;
		hr = psw.CreateInstance(__uuidof(SHDocVw::ShellWindows));
		if (FAILED(hr)) _com_issue_error(hr);
		
		_variant_t  varLoc(_bstr_t(URL));
		_variant_t VarRoot;
		long h = 0;
		IDispatchPtr pDisp = psw->FindWindowSW(&varLoc, &VarRoot, SWC_BROWSER, &h, SWFO_NEEDDISPATCH);
		
		SHDocVw::IWebBrowser2Ptr pBrowser(pDisp);
		MSHTML::IHTMLDocument2Ptr pDoc(pBrowser->Document);

		
		MSHTML::IHTMLWindow2Ptr pWin2( pDoc->parentWindow );
		IAccessiblePtr pAcc = nullptr;
		hr = IUnknown_QueryService( pWin2, __uuidof( IAccessible ), IID_PPV_ARGS( &pAcc ) );

		if( pAcc )
		{
			VARIANT varChild;
			varChild.vt = VT_I4;
			varChild.lVal = CHILDID_SELF;
					
			BSTR bstrName;
			pAcc->get_accName( varChild, &bstrName );
			
			MessageBox(nullptr,bstrName, nullptr,MB_OK );
			SysFreeString(bstrName);
		}
	}
	catch (_com_error& e) {
		hr = e.Error();
	}
	return hr;

}



int CALLBACK WinMain(
  _In_  HINSTANCE hInstance,
  _In_  HINSTANCE hPrevInstance,
  _In_  LPSTR lpCmdLine,
  _In_  int nCmdShow
)
{
	CoInitialize(NULL);
	test();
	CoUninitialize();
	return 0;
}