Rework window focus tracking for gamepad navigation

app/gui/sdlgamepadkeynavigation.h

@@ -20,6 +20,8 @@ public:
 
     Q_INVOKABLE void disable();
 
+    Q_INVOKABLE void notifyWindowFocus(bool hasFocus);
+
     Q_INVOKABLE void setUiNavMode(bool settingsMode);
 
     Q_INVOKABLE int getConnectedGamepads();
@@ -27,6 +29,8 @@ public:
 private:
     void sendKey(QEvent::Type type, Qt::Key key, Qt::KeyboardModifiers modifiers = Qt::NoModifier);
 
+    void updateTimerState();
+
 private slots:
     void onPollingTimerFired();
 
@@ -37,5 +41,6 @@ private:
     bool m_Enabled;
     bool m_UiNavMode;
     bool m_FirstPoll;
+    bool m_HasFocus;
     Uint32 m_LastAxisNavigationEventTime;
 };