Review improvements

flutter/lib/src/event_processor/native_app_start_event_processor.dart

@@ -23,7 +23,7 @@ class NativeAppStartEventProcessor implements EventProcessor {
 
     if (measurement != null) {
       event.measurements[measurement.name] = measurement;
-      _native.setDidAddAppStartMeasurement(true);
+      _native.didAddAppStartMeasurement = true;
     }
     return event;
   }

flutter/lib/src/frame_callback_handler.dart

@@ -7,6 +7,9 @@ abstract class FrameCallbackHandler {
 class DefaultFrameCallbackHandler implements FrameCallbackHandler {
   @override
   void addPostFrameCallback(FrameCallback callback) {
-    SchedulerBinding.instance.addPostFrameCallback(callback);
+    try {
+      /// Flutter >= 2.12 throws if SchedulerBinding.instance isn't initialized.
+      SchedulerBinding.instance.addPostFrameCallback(callback);
+    } catch (_) {}
   }
 }

flutter/lib/src/integrations/native_app_start_integration.dart

@@ -10,10 +10,10 @@ import '../event_processor/native_app_start_event_processor.dart';
 /// Integration which handles communication with native frameworks in order to
 /// enrich [SentryTransaction] objects with app start data for mobile vitals.
 class NativeAppStartIntegration extends Integration<SentryFlutterOptions> {
-  NativeAppStartIntegration(this._native, this._schedulerBindingProvider);
+  NativeAppStartIntegration(this._native, this._frameCallbackHandler);
 
   final SentryNative _native;
-  final SchedulerBindingProvider _schedulerBindingProvider;
+  final FrameCallbackHandler _frameCallbackHandler;
 
   /// We filter out App starts more than 60s
   static const _maxAppStartMillis = 60000;
@@ -48,54 +48,46 @@ class NativeAppStartIntegration extends Integration<SentryFlutterOptions> {
   @override
   void call(Hub hub, SentryFlutterOptions options) {
     if (options.autoAppStart) {
-      final schedulerBinding = _schedulerBindingProvider();
-      if (schedulerBinding == null) {
-        options.logger(SentryLevel.debug,
-            'Scheduler binding is null. Can\'t auto detect app start time.');
-      } else {
-        schedulerBinding.addPostFrameCallback((timeStamp) async {
-          if (_native.didFetchAppStart) {
-            setAppStartInfo(null);
-            return;
-          }
-
-          // We only assign the current time if it's not already set - this is useful in tests
-          // ignore: invalid_use_of_internal_member
-          _native.appStartEnd ??= options.clock();
-          final appStartEnd = _native.appStartEnd;
-          final nativeAppStart = await _native.fetchNativeAppStart();
-
-          if (nativeAppStart == null || appStartEnd == null) {
-            return;
-          }
-
-          final appStartDateTime = DateTime.fromMillisecondsSinceEpoch(
-              nativeAppStart.appStartTime.toInt());
-          final duration = appStartEnd.difference(appStartDateTime);
-
-          // We filter out app start more than 60s.
-          // This could be due to many different reasons.
-          // If you do the manual init and init the SDK too late and it does not
-          // compute the app start end in the very first Screen.
-          // If the process starts but the App isn't in the foreground.
-          // If the system forked the process earlier to accelerate the app start.
-          // And some unknown reasons that could not be reproduced.
-          // We've seen app starts with hours, days and even months.
-          if (duration.inMilliseconds > _maxAppStartMillis) {
-            setAppStartInfo(null);
-            return;
-          }
-
-          final appStartInfo = AppStartInfo(
-              nativeAppStart.isColdStart
-                  ? AppStartType.cold
-                  : AppStartType.warm,
-              start: DateTime.fromMillisecondsSinceEpoch(
-                  nativeAppStart.appStartTime.toInt()),
-              end: appStartEnd);
-          setAppStartInfo(appStartInfo);
-        });
-      }
+      _frameCallbackHandler.addPostFrameCallback((timeStamp) async {
+        if (_native.didFetchAppStart) {
+          setAppStartInfo(null);
+          return;
+        }
+
+        // We only assign the current time if it's not already set - this is useful in tests
+        // ignore: invalid_use_of_internal_member
+        _native.appStartEnd ??= options.clock();
+        final appStartEnd = _native.appStartEnd;
+        final nativeAppStart = await _native.fetchNativeAppStart();
+
+        if (nativeAppStart == null || appStartEnd == null) {
+          return;
+        }
+
+        final appStartDateTime = DateTime.fromMillisecondsSinceEpoch(
+            nativeAppStart.appStartTime.toInt());
+        final duration = appStartEnd.difference(appStartDateTime);
+
+        // We filter out app start more than 60s.
+        // This could be due to many different reasons.
+        // If you do the manual init and init the SDK too late and it does not
+        // compute the app start end in the very first Screen.
+        // If the process starts but the App isn't in the foreground.
+        // If the system forked the process earlier to accelerate the app start.
+        // And some unknown reasons that could not be reproduced.
+        // We've seen app starts with hours, days and even months.
+        if (duration.inMilliseconds > _maxAppStartMillis) {
+          setAppStartInfo(null);
+          return;
+        }
+
+        final appStartInfo = AppStartInfo(
+            nativeAppStart.isColdStart ? AppStartType.cold : AppStartType.warm,
+            start: DateTime.fromMillisecondsSinceEpoch(
+                nativeAppStart.appStartTime.toInt()),
+            end: appStartEnd);
+        setAppStartInfo(appStartInfo);
+      });
     }
 
     options.addEventProcessor(NativeAppStartEventProcessor(_native));
@@ -104,9 +96,6 @@ class NativeAppStartIntegration extends Integration<SentryFlutterOptions> {
   }
 }
 
-/// Used to provide scheduler binding at call time.
-typedef SchedulerBindingProvider = FrameCallbackHandler? Function();
-
 enum AppStartType { cold, warm }
 
 class AppStartInfo {

flutter/lib/src/native/sentry_native.dart

@@ -27,14 +27,8 @@ class SentryNative {
   /// Flag indicating if app start was already fetched.
   bool get didFetchAppStart => _didFetchAppStart;
 
-  bool _didAddAppStartMeasurement = false;
-
   /// Flag indicating if app start measurement was added to the first transaction.
-  bool get didAddAppStartMeasurement => _didAddAppStartMeasurement;
-
-  void setDidAddAppStartMeasurement(bool value) {
-    _didAddAppStartMeasurement = value;
-  }
+  bool didAddAppStartMeasurement = false;
 
   /// Fetch [NativeAppStart] from native channels. Can only be called once.
   Future<NativeAppStart?> fetchNativeAppStart() async {

flutter/lib/src/sentry_flutter.dart

@@ -189,13 +189,7 @@ mixin SentryFlutter {
     if (_native != null) {
       integrations.add(NativeAppStartIntegration(
         _native!,
-        () {
-          try {
-            /// Flutter >= 2.12 throws if SchedulerBinding.instance isn't initialized.
-            return DefaultFrameCallbackHandler();
-          } catch (_) {}
-          return null;
-        },
+        DefaultFrameCallbackHandler(),
       ));
     }
     return integrations;
@@ -231,6 +225,7 @@ mixin SentryFlutter {
 
   @internal
   static SentryNative? get native => _native;
+
   @internal
   static set native(SentryNative? value) => _native = value;
   static SentryNative? _native;

flutter/test/integrations/native_app_start_integration_test.dart

@@ -91,8 +91,8 @@ void main() {
       expect(enriched.measurements.isEmpty, true);
     });
 
-
-    test('native app start integration is called and sets app start info', () async {
+    test('native app start integration is called and sets app start info',
+        () async {
       fixture.native.appStartEnd = DateTime.fromMillisecondsSinceEpoch(10);
       fixture.binding.nativeAppStart = NativeAppStart(0, true);
 
@@ -119,10 +119,7 @@ class Fixture {
   NativeAppStartIntegration getNativeAppStartIntegration() {
     return NativeAppStartIntegration(
       native,
-      () {
-        TestWidgetsFlutterBinding.ensureInitialized();
-        return FakeFrameCallbackHandler();
-      },
+      FakeFrameCallbackHandler(),
     );
   }
 

flutter/test/mocks.dart

@@ -171,10 +171,8 @@ class TestMockSentryNative implements SentryNative {
   @override
   bool get didFetchAppStart => _didFetchAppStart;
 
-  bool _didAddAppStartMeasurement = false;
-
   @override
-  bool get didAddAppStartMeasurement => _didAddAppStartMeasurement;
+  bool didAddAppStartMeasurement = false;
 
   Breadcrumb? breadcrumb;
   var numberOfAddBreadcrumbCalls = 0;
@@ -295,11 +293,6 @@ class TestMockSentryNative implements SentryNative {
     numberOfDiscardProfilerCalls++;
     return Future.value(null);
   }
-
-  @override
-  void setDidAddAppStartMeasurement(bool value) {
-    _didAddAppStartMeasurement = value;
-  }
 }
 
 // TODO can this be replaced with https://pub.dev/packages/mockito#verifying-exact-number-of-invocations--at-least-x--never