Fix ios black screen during splash screen if widget binding initializ… (#52913)

packages/flutter/lib/src/scheduler/binding.dart

@@ -774,7 +774,7 @@ mixin SchedulerBinding on BindingBase, ServicesBinding {
   ///  * [scheduleWarmUpFrame], which ignores the "Vsync" signal entirely and
   ///    triggers a frame immediately.
   void scheduleFrame() {
-    if (_hasScheduledFrame || !_framesEnabled)
+    if (_hasScheduledFrame || !framesEnabled)
       return;
     assert(() {
       if (debugPrintScheduleFrameStacks)
@@ -808,7 +808,7 @@ mixin SchedulerBinding on BindingBase, ServicesBinding {
   void scheduleForcedFrame() {
     // TODO(chunhtai): Removes the if case once the issue is fixed
     // https://github.com/flutter/flutter/issues/45131
-    if (!_framesEnabled)
+    if (!framesEnabled)
       return;
 
     if (_hasScheduledFrame)

packages/flutter/lib/src/widgets/binding.dart

@@ -907,6 +907,11 @@ mixin WidgetsBinding on BindingBase, ServicesBinding, SchedulerBinding, GestureB
   Element get renderViewElement => _renderViewElement;
   Element _renderViewElement;
 
+  bool _readyToProduceFrames = false;
+
+  @override
+  bool get framesEnabled => super.framesEnabled && _readyToProduceFrames;
+
   /// Schedules a [Timer] for attaching the root widget.
   ///
   /// This is called by [runApp] to configure the widget tree. Consider using
@@ -928,6 +933,7 @@ mixin WidgetsBinding on BindingBase, ServicesBinding, SchedulerBinding, GestureB
   ///  * [RenderObjectToWidgetAdapter.attachToRenderTree], which inflates a
   ///    widget and attaches it to the render tree.
   void attachRootWidget(Widget rootWidget) {
+    _readyToProduceFrames = true;
     _renderViewElement = RenderObjectToWidgetAdapter<RenderBox>(
       container: renderView,
       debugShortDescription: '[root]',

packages/flutter/test/widgets/binding_cannot_schedule_frame_test.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:typed_data';
+
+import 'package:flutter/scheduler.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter/widgets.dart';
+
+void main() {
+  test('Can only schedule frames after widget binding attaches the root widget', () async {
+    final WidgetsBinding binding = WidgetsFlutterBinding.ensureInitialized();
+    expect(SchedulerBinding.instance.framesEnabled, isFalse);
+    expect(SchedulerBinding.instance.hasScheduledFrame, isFalse);
+    // Sends a message to notify that the engine is ready to accept frames.
+    final ByteData message = const StringCodec().encodeMessage('AppLifecycleState.resumed');
+    await ServicesBinding.instance.defaultBinaryMessenger.handlePlatformMessage('flutter/lifecycle', message, (_) { });
+
+    // Enables the semantics should not schedule any frames if the root widget
+    // has not been attached.
+    binding.setSemanticsEnabled(true);
+    expect(SchedulerBinding.instance.framesEnabled, isFalse);
+    expect(SchedulerBinding.instance.hasScheduledFrame, isFalse);
+
+    // The widget binding should be ready to produce frames after it attaches
+    // the root widget.
+    binding.attachRootWidget(const Placeholder());
+    expect(SchedulerBinding.instance.framesEnabled, isTrue);
+    expect(SchedulerBinding.instance.hasScheduledFrame, isTrue);
+  });
+}

packages/flutter/test/widgets/binding_frame_scheduling_test.dart

@@ -28,6 +28,9 @@ void main() {
     final ByteData message = const StringCodec().encodeMessage('AppLifecycleState.resumed');
     await ServicesBinding.instance.defaultBinaryMessenger.handlePlatformMessage('flutter/lifecycle', message, (_) { });
 
+    // A frame can only be scheduled when there is a root widget.
+    binding.attachRootWidget(const Placeholder());
+
     // Frame callbacks are registered lazily when a frame is scheduled.
     binding.scheduleFrame();
     expect(window.onBeginFrame, isNotNull);