Windows Accessibility: Use QWindowsAccessibility::windowHelper().

Amends changes ee516381,
d7a3b614

.

Task-number: QTBUG-52943
Change-Id: Icdf9d99c327bdd38dfb084e6cf77b14cd5ce073b
Reviewed-by: Jan Arve Sæther <jan-arve.saether@theqtcompany.com>

src/plugins/platforms/windows/accessible/qwindowsmsaaaccessible.cpp

@@ -470,15 +470,6 @@ HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::Invoke(long dispIdMember,
     return hr;
 }
 
-static const QWindow *windowOf(const QAccessibleInterface *ai)
-{
-    for ( ; ai; ai = ai->parent()) {
-        if (const QWindow *window = ai->window())
-            return window;
-    }
-    return Q_NULLPTR;
-}
-
 /*
   IAccessible
 
@@ -507,7 +498,8 @@ HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::accHitTest(long xLeft, long yT
     if (!accessible)
         return E_FAIL;
 
-    const QPoint pos = QHighDpi::fromNativeLocalPosition(QPoint(xLeft, yTop), windowOf(accessible));
+    const QPoint pos = QHighDpi::fromNativeLocalPosition(QPoint(xLeft, yTop),
+                                                         QWindowsAccessibility::windowHelper(accessible));
     QAccessibleInterface *child = accessible->childAt(pos.x(), pos.y());
     if (child == 0) {
         // no child found, return this item if it contains the coordinates
@@ -550,7 +542,8 @@ HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::accLocation(long *pxLeft, long
     QAccessibleInterface *acc = childPointer(accessible, varID);
     if (!acc || !acc->isValid())
         return E_FAIL;
-    const QRect rect = QHighDpi::toNativePixels(acc->rect(), windowOf(accessible));
+    const QRect rect = QHighDpi::toNativePixels(acc->rect(),
+                                                QWindowsAccessibility::windowHelper(accessible));
 
     *pxLeft = rect.x();
     *pyTop = rect.y();