App becomes Unresponsive after Repeated Clicking on Settings Menu

[pennzht]

Describe the bug
Repeatedly opening and closing sub-menus inside the settings menu raises errors, and causes the app to stop responding.

Flutter doctor
Copy and paste the output of flutter doctor -v here

[✓] Flutter (Channel master, 1.24.0-8.0.pre.178, on Mac OS X 10.15.6 19G2021 darwin-x64,
    locale en-DE)
    • Flutter version 1.24.0-8.0.pre.178 at /Users/tianguang/Documents/f/flutter
    • Framework revision 900da21f11 (35 minutes ago), 2020-11-10 03:54:03 -0500
    • Engine revision e50ac2c552
    • Dart version 2.12.0 (build 2.12.0-31.0.dev)

[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.3)
    • Android SDK at /Users/tianguang/Library/Android/sdk
    • Platform android-29, build-tools 29.0.3
    • Java binary at: /Applications/Android Studio with
      Blaze.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)
    • All Android licenses accepted.

[!] Xcode - develop for iOS and macOS (Xcode 11.2.1)
    • Xcode at /Applications/Xcode 11.2.1.app/Contents/Developer
    • Xcode 11.2.1, Build version 11B500
    ✗ CocoaPods installed but not working.
        You appear to have CocoaPods installed but it is not working.
        This can happen if the version of Ruby that CocoaPods was installed with is
        different from the one being used to invoke it.
        This can usually be fixed by re-installing CocoaPods.
      To re-install see
      https://guides.cocoapods.org/using/getting-started.html#installation for
      instructions.

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 4.1)
    • Android Studio at /Applications/Android Studio with Blaze.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)

[✓] Android Studio (version 3.5)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin version 39.0.3
    • Dart plugin version 191.8423
    • Java version OpenJDK Runtime Environment (build
      1.8.0_202-release-1483-b49-5587405)

[✓] Connected device (3 available)
    • macOS (desktop)  • macos      • darwin-x64     • Mac OS X 10.15.6 19G2021
      darwin-x64
    • Web Server (web) • web-server • web-javascript • Flutter Tools
    • Chrome (web)     • chrome     • web-javascript • Google Chrome 86.0.4240.193

! Doctor found issues in 1 category.

To Reproduce
Steps to reproduce the behavior:

1. Run the latest Gallery with latest Flutter, in Chrome. (flutter run -d chrome)
2. Open and close the settings menu on the top-end corner, a few times.
3. Open and close the menus inside the settings menu, a few times.
4. Sooner or later, an error similar to the following one will show up in the terminal.
5. After the error has been raised, the app becomes unresponsive; clicking anything has no effect.

The following assertion was thrown during a scheduler callback:
Assertion failed:
org-dartlang-sdk:///flutter_web_sdk/lib/_engine/engine/html/path/path_ref.dart:216:18
vector2_1y == 0.0
is not true

When the exception was thrown, this was the stack:
dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart 216:49  throw_
dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart 24:3
assertFailed
lib/_engine/engine/html/path/path_ref.dart 216:32
[_getRRect]
lib/_engine/engine/html/path/path_ref.dart 158:38                             getRRect
lib/_engine/engine/html/path/path.dart 1532:53                                get
webOnlyPathAsRoundedRect
lib/_engine/engine/html/clip.dart 198:38
recomputeTransformAndClip
lib/_engine/engine/html/surface.dart 558:5                                    preroll
lib/_engine/engine/html/surface.dart 640:11                                   preroll
lib/_engine/engine/html/surface.dart 643:18                                   preroll
lib/_engine/engine/html/surface.dart 643:18                                   preroll
lib/_engine/engine/html/surface.dart 643:18                                   preroll
lib/_engine/engine/html/surface.dart 643:18                                   preroll
lib/_engine/engine/html/surface.dart 643:18                                   preroll
lib/_engine/engine/html/surface.dart 643:18                                   preroll
lib/_engine/engine/html/surface.dart 643:18                                   preroll
lib/_engine/engine/html/surface.dart 643:18                                   preroll
lib/_engine/engine/html/surface.dart 643:18                                   preroll
lib/_engine/engine/html/surface.dart 643:18                                   preroll
lib/_engine/engine/html/scene_builder.dart 545:23                             <fn>
lib/_engine/engine/profiler.dart 36:18                                        timeAction
lib/_engine/engine/html/scene_builder.dart 540:5                              build
packages/flutter/src/rendering/layer.dart 770:35                              buildScene
packages/flutter/src/rendering/view.dart 231:30
compositeFrame
packages/flutter/src/rendering/binding.dart 458:18                            drawFrame
packages/flutter/src/widgets/binding.dart 900:13                              drawFrame
packages/flutter/src/rendering/binding.dart 320:5
[_handlePersistentFrameCallback]
packages/flutter/src/scheduler/binding.dart 1119:15
[_invokeFrameCallback]
packages/flutter/src/scheduler/binding.dart 1057:9
handleDrawFrame
packages/flutter/src/scheduler/binding.dart 973:5
[_handleDrawFrame]
lib/_engine/engine/platform_dispatcher.dart 892:13                            invoke
lib/_engine/engine/platform_dispatcher.dart 145:5
invokeOnDrawFrame
lib/_engine/engine.dart 240:45                                                <fn>
════════════════════════════════════════════════════════════════════════════════════════
════════════
Another exception was thrown: PersistedOffset: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.
Another exception was thrown: PersistedPhysicalShape: is in an unexpected state.

Expected behavior
The settings menu, as well as its sub-menus, should open and close without any errors.

Screenshots

Desktop (please complete the following information):

• OS: macOS 10.15.6
• Browser: Chrome 86.0.4240.183

Additional context
This error can be reproduced with many Flutter versions, as far as cd60da784f9f93708e75c8814782a7075270e615: Migrate Scaffold SnackBars in the framework to ScaffoldMessenger (#67946)

Since this error exists on master (with flare), it is independent from #369 and will not block it.

This issue exists even when using a simple static icon: See https://github.com/pennzht/newfluttergallery/tree/rough-x-migration for an example.

[pennzht]

Update: This issue exists even when using a simple static icon: See https://github.com/pennzht/newfluttergallery/tree/rough-x-migration for an example.