engine/src/flutter/lib/web_ui/dev/chrome.dart - mirrors/flutter.git - Git at Google

 // Copyright 2013 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 import 'dart:math' as math;

 import 'package:image/image.dart';
 import 'package:path/path.dart' as path;
 import 'package:test_api/backend.dart';
 import 'package:webkit_inspection_protocol/webkit_inspection_protocol.dart' as wip;

 import 'browser.dart';
 import 'browser_process.dart';
 import 'chrome_installer.dart';
 import 'common.dart';
 import 'environment.dart';
 import 'package_lock.dart';

 const String kBlankPageUrl = 'about:blank';

 /// Provides an environment for desktop Chrome.
 class ChromeEnvironment implements BrowserEnvironment {
   ChromeEnvironment({required bool useDwarf}) : _useDwarf = useDwarf;

   late final BrowserInstallation _installation;

   final bool _useDwarf;

   @override
   Future<Browser> launchBrowserInstance(Uri url, {bool debug = false}) async {
     return Chrome(url, _installation, debug: debug, useDwarf: _useDwarf);
   }

   @override
   Runtime get packageTestRuntime => Runtime.chrome;

   @override
   Future<void> prepare() async {
     final String version = packageLock.chromeLock.version;
     _installation = await getOrInstallChrome(version, infoLog: isCi ? stdout : DevNull());
   }

   @override
   Future<void> cleanup() async {}

   @override
   String get packageTestConfigurationYamlFile => 'dart_test_chrome.yaml';

   @override
   final String name = 'Chrome';
 }

 /// Runs desktop Chrome.
 ///
 /// Most of the communication with the browser is expected to happen via HTTP,
 /// so this exposes a bare-bones API. The browser starts as soon as the class is
 /// constructed, and is killed when [close] is called.
 ///
 /// Any errors starting or running the process are reported through [onExit].
 class Chrome extends Browser {
   /// Starts a new instance of Chrome open to the given [url], which may be a
   /// [Uri] or a [String].
   factory Chrome(
     Uri url,
     BrowserInstallation installation, {
     required bool debug,
     required bool useDwarf,
   }) {
     final Completer<Uri> remoteDebuggerCompleter = Completer<Uri>.sync();
     final Completer<String> exceptionCompleter = Completer<String>();
     return Chrome._(
       BrowserProcess(() async {
         // A good source of various Chrome CLI options:
         // https://peter.sh/experiments/chromium-command-line-switches/
         //
         // Things to try:
         // --font-render-hinting
         // --enable-font-antialiasing
         // --gpu-rasterization-msaa-sample-count
         // --disable-gpu
         // --disallow-non-exact-resource-reuse
         // --disable-font-subpixel-positioning
         final bool isChromeNoSandbox = Platform.environment['CHROME_NO_SANDBOX'] == 'true';
         final String dir = await generateUserDirectory(installation, useDwarf);
         final List<String> args = <String>[
           '--user-data-dir=$dir',
           kBlankPageUrl,
           if (!debug) '--headless',
           if (isChromeNoSandbox) '--no-sandbox',
           // When headless, this is the actual size of the viewport.
           if (!debug) '--window-size=$kMaxScreenshotWidth,$kMaxScreenshotHeight',
           // When debugging, run in maximized mode so there's enough room for DevTools.
           if (debug) '--start-maximized',
           if (debug) '--auto-open-devtools-for-tabs',
           if (useDwarf) '--devtools-flags=enabledExperiments=wasmDWARFDebugging',
           // Always run unit tests at a 1x scale factor
           '--force-device-scale-factor=1',
           if (!useDwarf)
             // DWARF debugging requires a Chrome extension.
             '--disable-extensions',
           '--disable-popup-blocking',
           // Indicates that the browser is in "browse without sign-in" (Guest session) mode.
           '--bwsi',
           '--no-first-run',
           '--no-default-browser-check',
           '--disable-default-apps',
           '--disable-translate',
           '--remote-debugging-port=$kDevtoolsPort',

           // SwiftShader support on ARM macs is disabled until they upgrade to a newer
           // version of LLVM, see https://issuetracker.google.com/issues/165000222. In
           // headless Chrome, the default is to use SwiftShader as a software renderer
           // for WebGL contexts. In order to work around this limitation, we can force
           // GPU rendering with this flag.
           if (environment.isMacosArm) '--use-angle=metal',
         ];

         final Process process = await _spawnChromiumProcess(installation.executable, args);

         await setupChromiumTab(url, exceptionCompleter);

         remoteDebuggerCompleter.complete(
           getRemoteDebuggerUrl(Uri.parse('http://localhost:$kDevtoolsPort')),
         );

         unawaited(process.exitCode.then((_) => Directory(dir).deleteSync(recursive: true)));

         return process;
       }),
       remoteDebuggerCompleter.future,
       exceptionCompleter.future,
     );
   }

   Chrome._(this._process, this.remoteDebuggerUrl, this._onUncaughtException);

   static Future<String> generateUserDirectory(
     BrowserInstallation installation,
     bool useDwarf,
   ) async {
     final String userDirectoryPath =
         environment.webUiDartToolDir
             .createTempSync('test_chrome_user_data_')
             .resolveSymbolicLinksSync();
     if (!useDwarf) {
       return userDirectoryPath;
     }

     // Using DWARF debugging info requires installation of a Chrome extension.
     // We can prompt for this, but in order to avoid prompting on every single
     // browser launch, we cache the user directory after it has been installed.
     final Directory baselineUserDirectory = Directory(
       path.join(environment.webUiDartToolDir.path, 'chrome_user_data_base'),
     );
     final Directory dwarfExtensionInstallDirectory = Directory(
       path.join(
         baselineUserDirectory.path,
         'Default',
         'Extensions',
         // This is the ID of the dwarf debugging extension.
         'pdcpmagijalfljmkmjngeonclgbbannb',
       ),
     );
     if (!baselineUserDirectory.existsSync()) {
       baselineUserDirectory.createSync(recursive: true);
     }
     if (!dwarfExtensionInstallDirectory.existsSync()) {
       print(
         'DWARF debugging requested. Launching Chrome. Please install the '
         'extension and then exit Chrome when the installation is complete...',
       );
       final Process addExtension = await Process.start(installation.executable, <String>[
         '--user-data-dir=${baselineUserDirectory.path}',
         'https://goo.gle/wasm-debugging-extension',
         '--bwsi',
         '--no-first-run',
         '--no-default-browser-check',
         '--disable-default-apps',
         '--disable-translate',
       ]);
       await addExtension.exitCode;
     }
     for (final FileSystemEntity input in baselineUserDirectory.listSync(recursive: true)) {
       final String relative = path.relative(input.path, from: baselineUserDirectory.path);
       final String outputPath = path.join(userDirectoryPath, relative);
       if (input is Directory) {
         await Directory(outputPath).create(recursive: true);
       } else if (input is File) {
         await input.copy(outputPath);
       }
     }
     return userDirectoryPath;
   }

   final BrowserProcess _process;

   final Future<String> _onUncaughtException;

   @override
   final Future<Uri> remoteDebuggerUrl;

   @override
   Future<void> get onExit => _process.onExit;

   @override
   Future<String>? get onUncaughtException => _onUncaughtException;

   @override
   Future<void> close() => _process.close();

   // Always compare screenshots when running tests locally. On CI only compare
   // on Linux.
   @override
   bool get supportsScreenshots => Platform.isLinux || !isLuci;

   /// Capture a screenshot of the web content.
   ///
   /// Uses Webkit Inspection Protocol server's `captureScreenshot` API.
   ///
   /// [region] is used to decide which part of the web content will be used in
   /// test image. It includes starting coordinate x,y as well as height and
   /// width of the area to capture.
   ///
   /// This method can be used for both macOS and Linux.
   // TODO(yjbanov): extends tests to Window, https://github.com/flutter/flutter/issues/65673
   @override
   Future<Image> captureScreenshot(math.Rectangle<num>? region) async {
     final wip.ChromeConnection chromeConnection = wip.ChromeConnection('localhost', kDevtoolsPort);
     final wip.ChromeTab? chromeTab = await chromeConnection.getTab(
       (wip.ChromeTab chromeTab) => chromeTab.url.contains('localhost'),
     );
     if (chromeTab == null) {
       throw StateError('Failed locate Chrome tab with the test page');
     }
     final wip.WipConnection wipConnection = await chromeTab.connect();

     Map<String, dynamic>? captureScreenshotParameters;
     if (region != null) {
       captureScreenshotParameters = <String, dynamic>{
         'format': 'png',
         'clip': <String, dynamic>{
           'x': region.left,
           'y': region.top,
           'width': region.width,
           'height': region.height,
           'scale':
               // This is NOT the DPI of the page, instead it's the "zoom level".
               1,
         },
       };
     }

     // Setting hardware-independent screen parameters:
     // https://chromedevtools.github.io/devtools-protocol/tot/Emulation
     await wipConnection.sendCommand('Emulation.setDeviceMetricsOverride', <String, dynamic>{
       'width': kMaxScreenshotWidth,
       'height': kMaxScreenshotHeight,
       'deviceScaleFactor': 1,
       'mobile': false,
     });
     final wip.WipResponse response = await wipConnection.sendCommand(
       'Page.captureScreenshot',
       captureScreenshotParameters,
     );

     final Image screenshot = decodePng(base64.decode(response.result!['data'] as String))!;

     return screenshot;
   }
 }

 /// Used by [Chrome] to detect a glibc bug and retry launching the
 /// browser.
 ///
 /// Once every few thousands of launches we hit this glibc bug:
 ///
 /// https://sourceware.org/bugzilla/show_bug.cgi?id=19329.
 ///
 /// When this happens Chrome spits out something like the following then exits with code 127:
 ///
 ///     Inconsistency detected by ld.so: ../elf/dl-tls.c: 493: _dl_allocate_tls_init: Assertion `listp->slotinfo[cnt].gen <= GL(dl_tls_generation)' failed!
 const String _kGlibcError = 'Inconsistency detected by ld.so';

 Future<Process> _spawnChromiumProcess(
   String executable,
   List<String> args, {
   String? workingDirectory,
 }) async {
   // Keep attempting to launch the browser until one of:
   // - Chrome launched successfully, in which case we just return from the loop.
   // - The tool detected an unretriable Chrome error, in which case we throw ToolExit.
   while (true) {
     final Process process = await Process.start(
       executable,
       args,
       workingDirectory: workingDirectory,
     );

     process.stdout.transform(utf8.decoder).transform(const LineSplitter()).listen((String line) {
       print('[CHROME STDOUT]: $line');
     });

     // Wait until the DevTools are listening before trying to connect. This is
     // only required for flutter_test --platform=chrome and not flutter run.
     bool hitGlibcBug = false;
     await process.stderr
         .transform(utf8.decoder)
         .transform(const LineSplitter())
         .map((String line) {
           print('[CHROME STDERR]:$line');
           if (line.contains(_kGlibcError)) {
             hitGlibcBug = true;
           }
           return line;
         })
         .firstWhere(
           (String line) => line.startsWith('DevTools listening'),
           orElse: () {
             if (hitGlibcBug) {
               const String message =
                   'Encountered glibc bug '
                   'https://sourceware.org/bugzilla/show_bug.cgi?id=19329. '
                   'Will try launching browser again.';
               print(message);
               return message;
             }
             print('Failed to launch browser. Command used to launch it: ${args.join(' ')}');
             throw Exception(
               'Failed to launch browser. Make sure you are using an up-to-date '
               'Chrome or Edge. Otherwise, consider using -d web-server instead '
               'and filing an issue at https://github.com/flutter/flutter/issues.',
             );
           },
         );

     if (!hitGlibcBug) {
       return process;
     }

     // A precaution that avoids accumulating browser processes, in case the
     // glibc bug doesn't cause the browser to quit and we keep looping and
     // launching more processes.

     // It's OK to not await the future here, as this is a best-effort process
     // clean-up only. If we're executing this line, this means things are off
     // the rails already due to the glibc bug, and we're just scrambling to keep
     // the system stable.
     // ignore: unawaited_futures
     process.exitCode.timeout(
       const Duration(seconds: 1),
       onTimeout: () {
         process.kill();
         return -1;
       },
     );
   }
 }

 /// Returns the full URL of the Chrome remote debugger for the main page.
 ///
 /// This takes the [base] remote debugger URL (which points to a browser-wide
 /// page) and uses its JSON API to find the resolved URL for debugging the host
 /// page.
 Future<Uri> getRemoteDebuggerUrl(Uri base) async {
   try {
     final HttpClient client = HttpClient();
     final HttpClientRequest request = await client.getUrl(base.resolve('/json/list'));
     final HttpClientResponse response = await request.close();
     final List<dynamic>? jsonObject =
         await json.fuse(utf8).decoder.bind(response).single as List<dynamic>?;
     return base.resolve(
       (jsonObject!.first as Map<dynamic, dynamic>)['devtoolsFrontendUrl'] as String,
     );
   } catch (_) {
     // If we fail to talk to the remote debugger protocol, give up and return
     // the raw URL rather than crashing.
     return base;
   }
 }

 Future<void> setupChromiumTab(Uri url, Completer<String> exceptionCompleter) async {
   final wip.ChromeConnection chromeConnection = wip.ChromeConnection('localhost', kDevtoolsPort);
   final wip.ChromeTab? chromeTab = await chromeConnection.getTab(
     (wip.ChromeTab chromeTab) => chromeTab.url == kBlankPageUrl,
   );
   final wip.WipConnection wipConnection = await chromeTab!.connect();

   await wipConnection.runtime.enable();

   wipConnection.runtime.onExceptionThrown.listen((wip.ExceptionThrownEvent event) {
     if (!exceptionCompleter.isCompleted) {
       final String text = event.exceptionDetails.text;
       final String? description = event.exceptionDetails.exception?.description;
       exceptionCompleter.complete('$text: $description');
     }
   });

   await wipConnection.page.enable();

   await wipConnection.page.navigate(url.toString());
 }
	// Copyright 2013 The Flutter Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	import 'dart:async';
	import 'dart:convert';
	import 'dart:io';
	import 'dart:math' as math;

	import 'package:image/image.dart';
	import 'package:path/path.dart' as path;
	import 'package:test_api/backend.dart';
	import 'package:webkit_inspection_protocol/webkit_inspection_protocol.dart' as wip;

	import 'browser.dart';
	import 'browser_process.dart';
	import 'chrome_installer.dart';
	import 'common.dart';
	import 'environment.dart';
	import 'package_lock.dart';

	const String kBlankPageUrl = 'about:blank';

	/// Provides an environment for desktop Chrome.
	class ChromeEnvironment implements BrowserEnvironment {
	ChromeEnvironment({required bool useDwarf}) : _useDwarf = useDwarf;

	late final BrowserInstallation _installation;

	final bool _useDwarf;

	@override
	Future<Browser> launchBrowserInstance(Uri url, {bool debug = false}) async {
	return Chrome(url, _installation, debug: debug, useDwarf: _useDwarf);
	}

	@override
	Runtime get packageTestRuntime => Runtime.chrome;

	@override
	Future<void> prepare() async {
	final String version = packageLock.chromeLock.version;
	_installation = await getOrInstallChrome(version, infoLog: isCi ? stdout : DevNull());
	}

	@override
	Future<void> cleanup() async {}

	@override
	String get packageTestConfigurationYamlFile => 'dart_test_chrome.yaml';

	@override
	final String name = 'Chrome';
	}

	/// Runs desktop Chrome.
	///
	/// Most of the communication with the browser is expected to happen via HTTP,
	/// so this exposes a bare-bones API. The browser starts as soon as the class is
	/// constructed, and is killed when [close] is called.
	///
	/// Any errors starting or running the process are reported through [onExit].
	class Chrome extends Browser {
	/// Starts a new instance of Chrome open to the given [url], which may be a
	/// [Uri] or a [String].
	factory Chrome(
	Uri url,
	BrowserInstallation installation, {
	required bool debug,
	required bool useDwarf,
	}) {
	final Completer<Uri> remoteDebuggerCompleter = Completer<Uri>.sync();
	final Completer<String> exceptionCompleter = Completer<String>();
	return Chrome._(
	BrowserProcess(() async {
	// A good source of various Chrome CLI options:
	// https://peter.sh/experiments/chromium-command-line-switches/
	//
	// Things to try:
	// --font-render-hinting
	// --enable-font-antialiasing
	// --gpu-rasterization-msaa-sample-count
	// --disable-gpu
	// --disallow-non-exact-resource-reuse
	// --disable-font-subpixel-positioning
	final bool isChromeNoSandbox = Platform.environment['CHROME_NO_SANDBOX'] == 'true';
	final String dir = await generateUserDirectory(installation, useDwarf);
	final List<String> args = <String>[
	'--user-data-dir=$dir',
	kBlankPageUrl,
	if (!debug) '--headless',
	if (isChromeNoSandbox) '--no-sandbox',
	// When headless, this is the actual size of the viewport.
	if (!debug) '--window-size=$kMaxScreenshotWidth,$kMaxScreenshotHeight',
	// When debugging, run in maximized mode so there's enough room for DevTools.
	if (debug) '--start-maximized',
	if (debug) '--auto-open-devtools-for-tabs',
	if (useDwarf) '--devtools-flags=enabledExperiments=wasmDWARFDebugging',
	// Always run unit tests at a 1x scale factor
	'--force-device-scale-factor=1',
	if (!useDwarf)
	// DWARF debugging requires a Chrome extension.
	'--disable-extensions',
	'--disable-popup-blocking',
	// Indicates that the browser is in "browse without sign-in" (Guest session) mode.
	'--bwsi',
	'--no-first-run',
	'--no-default-browser-check',
	'--disable-default-apps',
	'--disable-translate',
	'--remote-debugging-port=$kDevtoolsPort',

	// SwiftShader support on ARM macs is disabled until they upgrade to a newer
	// version of LLVM, see https://issuetracker.google.com/issues/165000222. In
	// headless Chrome, the default is to use SwiftShader as a software renderer
	// for WebGL contexts. In order to work around this limitation, we can force
	// GPU rendering with this flag.
	if (environment.isMacosArm) '--use-angle=metal',
	];

	final Process process = await _spawnChromiumProcess(installation.executable, args);

	await setupChromiumTab(url, exceptionCompleter);

	remoteDebuggerCompleter.complete(
	getRemoteDebuggerUrl(Uri.parse('http://localhost:$kDevtoolsPort')),
	);

	unawaited(process.exitCode.then((_) => Directory(dir).deleteSync(recursive: true)));

	return process;
	}),
	remoteDebuggerCompleter.future,
	exceptionCompleter.future,
	);
	}

	Chrome._(this._process, this.remoteDebuggerUrl, this._onUncaughtException);

	static Future<String> generateUserDirectory(
	BrowserInstallation installation,
	bool useDwarf,
	) async {
	final String userDirectoryPath =
	environment.webUiDartToolDir
	.createTempSync('test_chrome_user_data_')
	.resolveSymbolicLinksSync();
	if (!useDwarf) {
	return userDirectoryPath;
	}

	// Using DWARF debugging info requires installation of a Chrome extension.
	// We can prompt for this, but in order to avoid prompting on every single
	// browser launch, we cache the user directory after it has been installed.
	final Directory baselineUserDirectory = Directory(
	path.join(environment.webUiDartToolDir.path, 'chrome_user_data_base'),
	);
	final Directory dwarfExtensionInstallDirectory = Directory(
	path.join(
	baselineUserDirectory.path,
	'Default',
	'Extensions',
	// This is the ID of the dwarf debugging extension.
	'pdcpmagijalfljmkmjngeonclgbbannb',
	),
	);
	if (!baselineUserDirectory.existsSync()) {
	baselineUserDirectory.createSync(recursive: true);
	}
	if (!dwarfExtensionInstallDirectory.existsSync()) {
	print(
	'DWARF debugging requested. Launching Chrome. Please install the '
	'extension and then exit Chrome when the installation is complete...',
	);
	final Process addExtension = await Process.start(installation.executable, <String>[
	'--user-data-dir=${baselineUserDirectory.path}',
	'https://goo.gle/wasm-debugging-extension',
	'--bwsi',
	'--no-first-run',
	'--no-default-browser-check',
	'--disable-default-apps',
	'--disable-translate',
	]);
	await addExtension.exitCode;
	}
	for (final FileSystemEntity input in baselineUserDirectory.listSync(recursive: true)) {
	final String relative = path.relative(input.path, from: baselineUserDirectory.path);
	final String outputPath = path.join(userDirectoryPath, relative);
	if (input is Directory) {
	await Directory(outputPath).create(recursive: true);
	} else if (input is File) {
	await input.copy(outputPath);
	}
	}
	return userDirectoryPath;
	}

	final BrowserProcess _process;

	final Future<String> _onUncaughtException;

	@override
	final Future<Uri> remoteDebuggerUrl;

	@override
	Future<void> get onExit => _process.onExit;

	@override
	Future<String>? get onUncaughtException => _onUncaughtException;

	@override
	Future<void> close() => _process.close();

	// Always compare screenshots when running tests locally. On CI only compare
	// on Linux.
	@override
	bool get supportsScreenshots => Platform.isLinux \|\| !isLuci;

	/// Capture a screenshot of the web content.
	///
	/// Uses Webkit Inspection Protocol server's `captureScreenshot` API.
	///
	/// [region] is used to decide which part of the web content will be used in
	/// test image. It includes starting coordinate x,y as well as height and
	/// width of the area to capture.
	///
	/// This method can be used for both macOS and Linux.
	// TODO(yjbanov): extends tests to Window, https://github.com/flutter/flutter/issues/65673
	@override
	Future<Image> captureScreenshot(math.Rectangle<num>? region) async {
	final wip.ChromeConnection chromeConnection = wip.ChromeConnection('localhost', kDevtoolsPort);
	final wip.ChromeTab? chromeTab = await chromeConnection.getTab(
	(wip.ChromeTab chromeTab) => chromeTab.url.contains('localhost'),
	);
	if (chromeTab == null) {
	throw StateError('Failed locate Chrome tab with the test page');
	}
	final wip.WipConnection wipConnection = await chromeTab.connect();

	Map<String, dynamic>? captureScreenshotParameters;
	if (region != null) {
	captureScreenshotParameters = <String, dynamic>{
	'format': 'png',
	'clip': <String, dynamic>{
	'x': region.left,
	'y': region.top,
	'width': region.width,
	'height': region.height,
	'scale':
	// This is NOT the DPI of the page, instead it's the "zoom level".
	1,
	},
	};
	}

	// Setting hardware-independent screen parameters:
	// https://chromedevtools.github.io/devtools-protocol/tot/Emulation
	await wipConnection.sendCommand('Emulation.setDeviceMetricsOverride', <String, dynamic>{
	'width': kMaxScreenshotWidth,
	'height': kMaxScreenshotHeight,
	'deviceScaleFactor': 1,
	'mobile': false,
	});
	final wip.WipResponse response = await wipConnection.sendCommand(
	'Page.captureScreenshot',
	captureScreenshotParameters,
	);

	final Image screenshot = decodePng(base64.decode(response.result!['data'] as String))!;

	return screenshot;
	}
	}

	/// Used by [Chrome] to detect a glibc bug and retry launching the
	/// browser.
	///
	/// Once every few thousands of launches we hit this glibc bug:
	///
	/// https://sourceware.org/bugzilla/show_bug.cgi?id=19329.
	///
	/// When this happens Chrome spits out something like the following then exits with code 127:
	///
	/// Inconsistency detected by ld.so: ../elf/dl-tls.c: 493: _dl_allocate_tls_init: Assertion `listp->slotinfo[cnt].gen <= GL(dl_tls_generation)' failed!
	const String _kGlibcError = 'Inconsistency detected by ld.so';

	Future<Process> _spawnChromiumProcess(
	String executable,
	List<String> args, {
	String? workingDirectory,
	}) async {
	// Keep attempting to launch the browser until one of:
	// - Chrome launched successfully, in which case we just return from the loop.
	// - The tool detected an unretriable Chrome error, in which case we throw ToolExit.
	while (true) {
	final Process process = await Process.start(
	executable,
	args,
	workingDirectory: workingDirectory,
	);

	process.stdout.transform(utf8.decoder).transform(const LineSplitter()).listen((String line) {
	print('[CHROME STDOUT]: $line');
	});

	// Wait until the DevTools are listening before trying to connect. This is
	// only required for flutter_test --platform=chrome and not flutter run.
	bool hitGlibcBug = false;
	await process.stderr
	.transform(utf8.decoder)
	.transform(const LineSplitter())
	.map((String line) {
	print('[CHROME STDERR]:$line');
	if (line.contains(_kGlibcError)) {
	hitGlibcBug = true;
	}
	return line;
	})
	.firstWhere(
	(String line) => line.startsWith('DevTools listening'),
	orElse: () {
	if (hitGlibcBug) {
	const String message =
	'Encountered glibc bug '
	'https://sourceware.org/bugzilla/show_bug.cgi?id=19329. '
	'Will try launching browser again.';
	print(message);
	return message;
	}
	print('Failed to launch browser. Command used to launch it: ${args.join(' ')}');
	throw Exception(
	'Failed to launch browser. Make sure you are using an up-to-date '
	'Chrome or Edge. Otherwise, consider using -d web-server instead '
	'and filing an issue at https://github.com/flutter/flutter/issues.',
	);
	},
	);

	if (!hitGlibcBug) {
	return process;
	}

	// A precaution that avoids accumulating browser processes, in case the
	// glibc bug doesn't cause the browser to quit and we keep looping and
	// launching more processes.

	// It's OK to not await the future here, as this is a best-effort process
	// clean-up only. If we're executing this line, this means things are off
	// the rails already due to the glibc bug, and we're just scrambling to keep
	// the system stable.
	// ignore: unawaited_futures
	process.exitCode.timeout(
	const Duration(seconds: 1),
	onTimeout: () {
	process.kill();
	return -1;
	},
	);
	}
	}

	/// Returns the full URL of the Chrome remote debugger for the main page.
	///
	/// This takes the [base] remote debugger URL (which points to a browser-wide
	/// page) and uses its JSON API to find the resolved URL for debugging the host
	/// page.
	Future<Uri> getRemoteDebuggerUrl(Uri base) async {
	try {
	final HttpClient client = HttpClient();
	final HttpClientRequest request = await client.getUrl(base.resolve('/json/list'));
	final HttpClientResponse response = await request.close();
	final List<dynamic>? jsonObject =
	await json.fuse(utf8).decoder.bind(response).single as List<dynamic>?;
	return base.resolve(
	(jsonObject!.first as Map<dynamic, dynamic>)['devtoolsFrontendUrl'] as String,
	);
	} catch (_) {
	// If we fail to talk to the remote debugger protocol, give up and return
	// the raw URL rather than crashing.
	return base;
	}
	}

	Future<void> setupChromiumTab(Uri url, Completer<String> exceptionCompleter) async {
	final wip.ChromeConnection chromeConnection = wip.ChromeConnection('localhost', kDevtoolsPort);
	final wip.ChromeTab? chromeTab = await chromeConnection.getTab(
	(wip.ChromeTab chromeTab) => chromeTab.url == kBlankPageUrl,
	);
	final wip.WipConnection wipConnection = await chromeTab!.connect();

	await wipConnection.runtime.enable();

	wipConnection.runtime.onExceptionThrown.listen((wip.ExceptionThrownEvent event) {
	if (!exceptionCompleter.isCompleted) {
	final String text = event.exceptionDetails.text;
	final String? description = event.exceptionDetails.exception?.description;
	exceptionCompleter.complete('$text: $description');
	}
	});

	await wipConnection.page.enable();

	await wipConnection.page.navigate(url.toString());
	}