wasm: use QWasmWindow::fromWindow()

Make it test for null QWindow and handle(), use it
instead of C-style casting handle().

Change-Id: I7ffb1ef5d3d3c09c8ae44ec0141e93530a04abe6
Reviewed-by: Even Oscar Andersen <[email protected]>
Reviewed-by: Piotr Wierciński <[email protected]>

Author: Morten Sørvig

src/plugins/platforms/wasm/qwasminputcontext.cpp

@@ -327,8 +327,8 @@ void QWasmInputContext::updateInputElement()
         m_inputElement.set("value", "");
 
         m_inputElement.call<void>("blur");
-        if (focusWindow && focusWindow->handle())
-            ((QWasmWindow *)(focusWindow->handle()))->focus();
+        if (QWasmWindow *wasmwindow = QWasmWindow::fromWindow(focusWindow))
+            wasmwindow->focus();
 
         return;
     }

src/plugins/platforms/wasm/qwasmwindow.cpp

@@ -211,8 +211,10 @@ QSurfaceFormat QWasmWindow::format() const
     return window()->requestedFormat();
 }
 
-QWasmWindow *QWasmWindow::fromWindow(QWindow *window)
+QWasmWindow *QWasmWindow::fromWindow(const QWindow *window)
 {
+    if (!window ||!window->handle())
+        return nullptr;
     return static_cast<QWasmWindow *>(window->handle());
 }
 

src/plugins/platforms/wasm/qwasmwindow.h

@@ -45,7 +45,7 @@ class QWasmWindow final : public QPlatformWindow,
                 QWasmBackingStore *backingStore, WId nativeHandle);
     ~QWasmWindow() final;
 
-    static QWasmWindow *fromWindow(QWindow *window);
+    static QWasmWindow *fromWindow(const QWindow *window);
     QSurfaceFormat format() const override;
 
     void registerEventHandlers();