Repository: flutter
Issue: [tool_crash] FileSystemException: Cannot open file, OS Error: No such file or directory, errno = 2
Labels: c: crash,tool,platform-web,P2,team-web,triaged-web

I wanted to test dart app for the web with flutter and engine built in local host. I might be missed something while I built dart for beta channel.


## Command
```
flutter --local-engine-src-path /Users/ragingwind/Workspace/_flutter/flutter/engine/src --local-engine=host_debug_unopt run -d chrome
```

## Steps to Reproduce
1. Clone flutter and engine
2. Build engine flowing this [instruction](https://github.com/flutter/flutter/wiki/Compiling-the-engine#compiling-for-macos-or-linux)
3. Enable web feature flowing this [step](https://flutter.dev/docs/get-started/web#set-up)
4. flutter --local-engine-src-path ~/Workspace/_flutter/flutter/engine/src --local-engine=host_debug_unopt run -d Chrome


## Logs
FileSystemException: Cannot open file, OS Error: No such file or directory, errno = 2
```
#0      _File.throwIfError (dart:io/file_impl.dart:635:7)
#1      _File.openSync (dart:io/file_impl.dart:479:5)
#2      _File.readAsBytesSync (dart:io/file_impl.dart:539:18)
#3      ForwardingFile.readAsBytesSync (package:file/src/forwarding/forwarding_file.dart:89:43)
#4      ForwardingFile.readAsBytesSync (package:file/src/forwarding/forwarding_file.dart:89:43)
#5      WebDevFS.update (package:flutter_tools/src/isolated/devfs_web.dart:833:57)
#6      _ResidentWebRunner._updateDevFS (package:flutter_tools/src/isolated/resident_web_runner.dart:736:54)
<asynchronous suspension>
#7      _ResidentWebRunner.run.<anonymous closure> (package:flutter_tools/src/isolated/resident_web_runner.dart:518:47)
<asynchronous suspension>
#8      _ResidentWebRunner.run.<anonymous closure> (package:flutter_tools/src/isolated/resident_web_runner.dart)
#9      asyncGuard.<anonymous closure> (package:flutter_tools/src/base/async_guard.dart:111:32)
#10     _rootRun (dart:async/zone.dart:1190:13)
#11     _CustomZone.run (dart:async/zone.dart:1093:19)
#12     _runZoned (dart:async/zone.dart:1630:10)
#13     runZonedGuarded (dart:async/zone.dart:1618:12)
#14     runZoned (dart:async/zone.dart:1547:12)
#15     asyncGuard (package:flutter_tools/src/base/async_guard.dart:109:3)
#16     _ResidentWebRunner.run (package:flutter_tools/src/isolated/resident_web_runner.dart:496:20)
<asynchronous suspension>
#17     RunCommand.runCommand (package:flutter_tools/src/commands/run.dart:613:37)
<asynchronous suspension>
#18     FlutterCommand.verifyThenRunCommand (package:flutter_tools/src/runner/flutter_command.dart:1005:18)
#19     _rootRunUnary (dart:async/zone.dart:1198:47)
#20     _CustomZone.runUnary (dart:async/zone.dart:1100:19)
```
```
[✓] Flutter (Channel beta, 1.23.0-18.1.pre, on Mac OS X 10.15.6 19G2021 x86_64, locale en-US)
    • Flutter version 1.23.0-18.1.pre at /Users/ragingwind/Workspace/_flutter/flutter
    • Framework revision 198df796aa (9 days ago), 2020-10-15 12:04:33 -0700
    • Engine revision 1d12d82d9c
    • Dart version 2.11.0 (build 2.11.0-213.1.beta)

[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.2)
    • Android SDK at /Users/ragingwind/Library/Android/sdk
    • Platform android-29, build-tools 29.0.2
    • ANDROID_SDK_ROOT = /Users/ragingwind/Library/Android/sdk
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_212-release-1586-b4-5784211)
    • All Android licenses accepted.

[!] Xcode - develop for iOS and macOS (Xcode 12.0)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 12.0, Build version 12A7209
    ✗ CocoaPods not installed.
        CocoaPods is used to retrieve the iOS and macOS platform side's plugin code that responds to
        your plugin usage on the Dart side.
        Without CocoaPods, plugins will not work on iOS or macOS.
        For more info, see https://flutter.dev/platform-plugins
      To install:
        sudo gem install cocoapods

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 3.6)
    • Android Studio at /Applications/Android Studio.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_212-release-1586-b4-5784211)

[✓] IntelliJ IDEA Ultimate Edition (version 2020.2.1)
    • IntelliJ at /Applications/IntelliJ IDEA.app
    • 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

[✓] VS Code (version 1.50.1)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.15.1

[✓] Connected device (2 available)
    • Web Server (web) • web-server • web-javascript • Flutter Tools
    • Chrome (web)     • chrome     • web-javascript • Google Chrome 86.0.4240.111

! Doctor found issues in 1 category.

```

## Flutter Application Metadata
**Type**: app
**Version**: 1.0.0+1
**Material**: true
**Android X**: false
**Module**: false
**Plugin**: false
**Android package**: null
**iOS bundle identifier**: null
**Creation channel**: beta
**Creation framework version**: 198df796aa80073ef22bdf249e614e2ff33c6895