mshtml: Silence IExternalConnection in htmldoc_qi FIXME.

dlls/mshtml/htmldoc.c

@@ -1773,6 +1773,9 @@ static BOOL htmldoc_qi(HTMLDocument *This, REFIID riid, void **ppv)
     }else if(IsEqualGUID(&IID_IMarshal, riid)) {
         TRACE("(%p)->(IID_IMarshal %p) returning NULL\n", This, ppv);
         *ppv = NULL;
+    }else if(IsEqualGUID(&IID_IExternalConnection, riid)) {
+        TRACE("(%p)->(IID_IExternalConnection %p) returning NULL\n", This, ppv);
+        *ppv = NULL;
     }else if(IsEqualGUID(&IID_IObjectWithSite, riid)) {
         TRACE("(%p)->(IID_IObjectWithSite %p)\n", This, ppv);
         *ppv = OBJSITE(This);

dlls/mshtml/tests/htmldoc.c

@@ -4309,6 +4309,11 @@ static void test_QueryInterface(IHTMLDocument2 *doc)
     hres = IUnknown_QueryInterface(doc, &IID_IMarshal, (void**)&qi);
     ok(hres == E_NOINTERFACE, "QueryInterface returned %08x, expected E_NOINTERFACE\n", hres);
     ok(qi == NULL, "qi=%p, expected NULL\n", qi);
+
+    qi = (void*)0xdeadbeef;
+    hres = IUnknown_QueryInterface(doc, &IID_IExternalConnection, (void**)&qi);
+    ok(hres == E_NOINTERFACE, "QueryInterface returned %08x, expected E_NOINTERFACE\n", hres);
+    ok(qi == NULL, "qi=%p, expected NULL\n", qi);
 }
 
 static void init_test(enum load_state_t ls) {