dxdiagn: Fix a return value and avoid validating the input parameter for…

dlls/dxdiagn/provider.c

@@ -110,11 +110,8 @@ static HRESULT WINAPI IDxDiagProviderImpl_GetRootContainer(PDXDIAGPROVIDER iface
   IDxDiagProviderImpl *This = (IDxDiagProviderImpl *)iface;
   TRACE("(%p,%p)\n", iface, ppInstance);
 
-  if (NULL == ppInstance) {
-    return E_INVALIDARG;
-  }
   if (FALSE == This->init) {
-    return E_INVALIDARG; /* should be E_CO_UNINITIALIZED */
+    return CO_E_NOTINITIALIZED;
   }
   if (NULL == This->pRootContainer) {
     hr = DXDiag_CreateDXDiagContainer(&IID_IDxDiagContainer, (void**) &This->pRootContainer);

dlls/dxdiagn/tests/provider.c

@@ -107,12 +107,10 @@ static void test_GetRootContainer(void)
 
     /* Test calling IDxDiagProvider::GetRootContainer before initialization. */
     hr = IDxDiagProvider_GetRootContainer(pddp, NULL);
-    todo_wine
     ok(hr == CO_E_NOTINITIALIZED,
        "Expected IDxDiagProvider::GetRootContainer to return CO_E_NOTINITIALIZED, got %x\n", hr);
 
     hr = IDxDiagProvider_GetRootContainer(pddp, &pddc);
-    todo_wine
     ok(hr == CO_E_NOTINITIALIZED,
        "Expected IDxDiagProvider::GetRootContainer to return CO_E_NOTINITIALIZED, got %x\n", hr);