Part 1 for https://github.com/flutter/flutter/issues/55969 workaround

flutter.patch

diff --git a/packages/flutter/lib/src/foundation/binding.dart b/packages/flutter/lib/src/foundation/binding.dart
index 957f85906..779f320a5 100644
--- a/packages/flutter/lib/src/foundation/binding.dart
+++ b/packages/flutter/lib/src/foundation/binding.dart
@@ -50,16 +50,24 @@ abstract class BindingBase {
   /// instance pointers and other state, then calls
   /// [initServiceExtensions] to have bindings initialize their
   /// observatory service extensions, if any.
-  BindingBase() {
+  BindingBase({bool background = false}) {
     developer.Timeline.startSync('Framework initialization');
 
-    assert(!_debugInitialized);
-    initInstances();
-    assert(_debugInitialized);
+    if (background != null && background) {
+      initBackgroundInstances();
 
-    assert(!_debugServiceExtensionsRegistered);
-    initServiceExtensions();
-    assert(_debugServiceExtensionsRegistered);
+      // assert(!_debugServiceExtensionsRegistered);
+      // initServiceExtensions();
+      // assert(_debugServiceExtensionsRegistered);
+    } else {
+      assert(!_debugInitialized);
+      initInstances();
+      assert(_debugInitialized);
+
+      assert(!_debugServiceExtensionsRegistered);
+      initServiceExtensions();
+      assert(_debugServiceExtensionsRegistered);
+    }
 
     developer.postEvent('Flutter.FrameworkInitialization', <String, String>{});
 
@@ -87,6 +95,10 @@ abstract class BindingBase {
   /// different [Window] implementation, such as a [TestWindow].
   ui.Window get window => ui.window;
 
+  @protected
+  void initBackgroundInstances() {
+  }
+
   /// The initialization method. Subclasses override this method to hook into
   /// the platform and otherwise configure their services. Subclasses must call
   /// "super.initInstances()".
diff --git a/packages/flutter/lib/src/services/binding.dart b/packages/flutter/lib/src/services/binding.dart
index 227b9070d..cf23d931b 100644
--- a/packages/flutter/lib/src/services/binding.dart
+++ b/packages/flutter/lib/src/services/binding.dart
@@ -19,6 +19,16 @@ import 'system_channels.dart';
 /// bundle, and implements the `ext.flutter.evict` service extension (see
 /// [evict]).
 mixin ServicesBinding on BindingBase {
+  @override
+  void initBackgroundInstances() {
+    super.initBackgroundInstances();
+    _instance = this;
+    _defaultBinaryMessenger = createBinaryMessenger();
+    window.onPlatformMessage = defaultBinaryMessenger.handlePlatformMessage;
+    initLicenses();
+    SystemChannels.system.setMessageHandler(handleSystemMessage);
+  }
+
   @override
   void initInstances() {
     super.initInstances();
diff --git a/packages/flutter/lib/src/widgets/binding.dart b/packages/flutter/lib/src/widgets/binding.dart
index d511001d6..72356e771 100644
--- a/packages/flutter/lib/src/widgets/binding.dart
+++ b/packages/flutter/lib/src/widgets/binding.dart
@@ -250,6 +250,14 @@ abstract class WidgetsBindingObserver {
 
 /// The glue between the widgets layer and the Flutter engine.
 mixin WidgetsBinding on BindingBase, ServicesBinding, SchedulerBinding, GestureBinding, RendererBinding, SemanticsBinding {
+  @override
+  @protected
+  void initBackgroundInstances() {
+    super.initBackgroundInstances();
+
+    _backgroundInstance = this;
+  }
+
   @override
   void initInstances() {
     super.initInstances();
@@ -352,6 +360,9 @@ mixin WidgetsBinding on BindingBase, ServicesBinding, SchedulerBinding, GestureB
     ));
   }
 
+  static WidgetsBinding get backgroundInstance => _backgroundInstance;
+  static WidgetsBinding _backgroundInstance;
+
   /// The current [WidgetsBinding], if one has been created.
   ///
   /// If you need the binding to be constructed before calling [runApp],
@@ -1186,6 +1197,13 @@ class RenderObjectToWidgetElement<T extends RenderObject> extends RootRenderObje
 ///
 /// This is the glue that binds the framework to the Flutter engine.
 class WidgetsFlutterBinding extends BindingBase with GestureBinding, ServicesBinding, SchedulerBinding, PaintingBinding, SemanticsBinding, RendererBinding, WidgetsBinding {
+  WidgetsFlutterBinding({bool background,}) : super(background: background);
+
+  static WidgetsBinding ensureBackgroundInitialized() {
+    if (WidgetsBinding.backgroundInstance == null)
+      WidgetsFlutterBinding(background: true);
+    return WidgetsBinding.backgroundInstance;
+  }
 
   /// Returns an instance of the [WidgetsBinding], creating and
   /// initializing it if necessary. If one is created, it will be a
diff --git a/packages/flutter/lib/src/widgets/widget_inspector.dart b/packages/flutter/lib/src/widgets/widget_inspector.dart
index 4d021afd8..e0905d2e8 100644
--- a/packages/flutter/lib/src/widgets/widget_inspector.dart
+++ b/packages/flutter/lib/src/widgets/widget_inspector.dart
@@ -956,7 +956,7 @@ mixin WidgetInspectorService {
       return true;
     }());
 
-    SchedulerBinding.instance.addPersistentFrameCallback(_onFrameStart);
+    SchedulerBinding.instance?.addPersistentFrameCallback(_onFrameStart);
 
     final FlutterExceptionHandler structuredExceptionHandler = _reportError;
     final FlutterExceptionHandler defaultExceptionHandler = FlutterError.onError;