feat: pause the activity of webf when app visibility changed.

Author: andycall

webf/lib/src/launcher/controller.dart

@@ -709,14 +709,17 @@ class WebFViewController implements WidgetsBindingObserver {
     switch (state) {
       case AppLifecycleState.resumed:
         document.visibilityChange(VisibilityState.visible);
+        rootController.resume();
         break;
       case AppLifecycleState.hidden:
       case AppLifecycleState.paused:
         document.visibilityChange(VisibilityState.hidden);
+        rootController.pause();
         break;
       case AppLifecycleState.inactive:
         break;
       case AppLifecycleState.detached:
+        rootController.pause();
         break;
     }
   }
@@ -1344,6 +1347,7 @@ class WebFController {
     module.resumeAnimationFrame();
     view.resumeAnimationTimeline();
     view.document.reactiveWidgetElements();
+    SchedulerBinding.instance.scheduleFrame();
   }
 
   bool _disposed = false;