From 13cdf933d64195715e46535866bded85c1c1fe3f Mon Sep 17 00:00:00 2001
From: Victoria Ashworth <15619084+vashworth@users.noreply.github.com>
Date: Thu, 16 Nov 2023 13:02:57 -0600
Subject: [PATCH] Fix race condition in Unobstructed Platform View Scenario
 tests (#48096)

Fixes race situation where `_onPlatformMessage` is triggered before the first frame, essentially skipping the first frame.

Fixes https://github.com/flutter/flutter/issues/138193.

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style
---
 testing/scenario_app/lib/src/platform_view.dart | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/testing/scenario_app/lib/src/platform_view.dart b/testing/scenario_app/lib/src/platform_view.dart
index 39e6d42c16c97..d232546f76dcd 100644
--- a/testing/scenario_app/lib/src/platform_view.dart
+++ b/testing/scenario_app/lib/src/platform_view.dart
@@ -422,7 +422,6 @@ class MultiPlatformViewBackgroundForegroundScenario extends Scenario
     required this.secondId,
   }) {
     _nextFrame = _firstFrame;
-    channelBuffers.setListener('flutter/lifecycle', _onPlatformMessage);
   }
 
   /// The platform view identifier to use for the first platform view.
@@ -438,7 +437,13 @@ class MultiPlatformViewBackgroundForegroundScenario extends Scenario
     _nextFrame();
   }
 
+  bool _firstFrameBegan = false;
+
   void _firstFrame() {
+    if (!_firstFrameBegan) {
+      channelBuffers.setListener('flutter/lifecycle', _onPlatformMessage);
+    }
+    _firstFrameBegan = true;
     final SceneBuilder builder = SceneBuilder();
 
     builder.pushOffset(50, 600);