From c6c50cfe04d52b5fb3f2cb3695dcc2fc7c7015e7 Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Mon, 28 Nov 2022 14:58:38 -0800
Subject: [PATCH 1/9] Pull out debug logging into one file

---
 dwds/debug_extension_mv3/web/background.dart  |  4 +-
 dwds/debug_extension_mv3/web/detector.dart    |  4 +-
 .../web/lifeline_connection.dart              |  8 ++--
 .../web/lifeline_ports.dart                   | 40 ++++++----------
 dwds/debug_extension_mv3/web/logger.dart      | 47 +++++++++++++++++++
 dwds/debug_extension_mv3/web/messaging.dart   |  4 +-
 dwds/debug_extension_mv3/web/storage.dart     | 23 ++-------
 dwds/debug_extension_mv3/web/web_api.dart     |  3 ++
 8 files changed, 80 insertions(+), 53 deletions(-)
 create mode 100644 dwds/debug_extension_mv3/web/logger.dart

diff --git a/dwds/debug_extension_mv3/web/background.dart b/dwds/debug_extension_mv3/web/background.dart
index 9de0c0f60..f1b853444 100644
--- a/dwds/debug_extension_mv3/web/background.dart
+++ b/dwds/debug_extension_mv3/web/background.dart
@@ -15,6 +15,7 @@ import 'package:js/js.dart';
 import 'chrome_api.dart';
 import 'data_types.dart';
 import 'lifeline_ports.dart';
+import 'logger.dart';
 import 'messaging.dart';
 import 'storage.dart';
 import 'web_api.dart';
@@ -68,6 +69,7 @@ Future<bool> _authenticateUser(String extensionUrl, int tabId) async {
   final response = await fetchRequest(authUrl);
   final responseBody = response.body ?? '';
   if (!responseBody.contains(_authSuccessResponse)) {
+    debugWarn('Not authenticated: ${response.status} / $responseBody');
     _showWarningNotification('Please re-authenticate and try again.');
     await _createTab(authUrl, inNewWindow: false);
     return false;
@@ -98,7 +100,7 @@ void _handleRuntimeMessages(
       messageHandler: (DebugInfo debugInfo) async {
         final dartTab = sender.tab;
         if (dartTab == null) {
-          console.warn('Received debug info but tab is missing.');
+          debugWarn('Received debug info but tab is missing.');
           return;
         }
         // Save the debug info for the Dart app in storage:
diff --git a/dwds/debug_extension_mv3/web/detector.dart b/dwds/debug_extension_mv3/web/detector.dart
index ca4be0c56..35bf64bc6 100644
--- a/dwds/debug_extension_mv3/web/detector.dart
+++ b/dwds/debug_extension_mv3/web/detector.dart
@@ -10,8 +10,8 @@ import 'dart:js_util';
 import 'package:js/js.dart';
 
 import 'chrome_api.dart';
+import 'logger.dart';
 import 'messaging.dart';
-import 'web_api.dart';
 
 void main() {
   _registerListeners();
@@ -24,7 +24,7 @@ void _registerListeners() {
 void _onDartAppReadyEvent(Event event) {
   final debugInfo = getProperty(event, 'detail') as String?;
   if (debugInfo == null) {
-    console.warn('Can\'t debug Dart app without debug info.');
+    debugWarn('Can\'t debug Dart app without debug info.');
     return;
   }
   _sendMessageToBackgroundScript(
diff --git a/dwds/debug_extension_mv3/web/lifeline_connection.dart b/dwds/debug_extension_mv3/web/lifeline_connection.dart
index ec32786b9..3096a9566 100644
--- a/dwds/debug_extension_mv3/web/lifeline_connection.dart
+++ b/dwds/debug_extension_mv3/web/lifeline_connection.dart
@@ -3,15 +3,17 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'chrome_api.dart';
-import 'web_api.dart';
+import 'logger.dart';
 
 void main() async {
   _connectToLifelinePort();
 }
 
 void _connectToLifelinePort() {
-  console.log(
-      '[Dart Debug Extension] Connecting to lifeline port at ${_currentTime()}.');
+  debugLog(
+    'Connecting to lifeline port at ${_currentTime()}.',
+    prefix: 'Dart Debug Extension',
+  );
   chrome.runtime.connect(
     /*extensionId=*/ null,
     ConnectInfo(name: 'keepAlive'),
diff --git a/dwds/debug_extension_mv3/web/lifeline_ports.dart b/dwds/debug_extension_mv3/web/lifeline_ports.dart
index a465cebbd..23f57ed62 100644
--- a/dwds/debug_extension_mv3/web/lifeline_ports.dart
+++ b/dwds/debug_extension_mv3/web/lifeline_ports.dart
@@ -12,7 +12,7 @@ import 'dart:async';
 import 'package:js/js.dart';
 
 import 'chrome_api.dart';
-import 'web_api.dart';
+import 'logger.dart';
 
 // Switch to true to enable debug logs.
 // TODO(elliette): Enable / disable with flag while building the extension.
@@ -26,18 +26,18 @@ void maybeCreateLifelinePort(int tabId) {
   // Keep track of current Dart tabs that are being debugged. This way if one of
   // them is closed, we can reconnect the lifeline port to another one:
   dartTabs.add(tabId);
-  _debugLog('Dart tabs are: $dartTabs');
+  debugLog('Dart tabs are: $dartTabs');
   // Don't create a lifeline port if we already have one (meaning another Dart
   // app is currently being debugged):
   if (lifelinePort != null) {
-    _debugWarn('Port already exists.');
+    debugWarn('Port already exists.');
     return;
   }
   // Start the keep-alive logic when the port connects:
   chrome.runtime.onConnect.addListener(allowInterop(_keepLifelinePortAlive));
   // Inject the connection script into the current Dart tab, that way the tab
   // will connect to the port:
-  _debugLog('Creating lifeline port.');
+  debugLog('Creating lifeline port.');
   lifelineTab = tabId;
   chrome.scripting.executeScript(
     InjectDetails(
@@ -52,17 +52,17 @@ void maybeRemoveLifelinePort(int removedTabId) {
   final removedDartTab = dartTabs.remove(removedTabId);
   // If the removed tab was not a Dart tab, return early.
   if (!removedDartTab) return;
-  _debugLog('Removed tab $removedTabId, Dart tabs are now $dartTabs.');
+  debugLog('Removed tab $removedTabId, Dart tabs are now $dartTabs.');
   // If the removed Dart tab hosted the lifeline port connection, see if there
   // are any other Dart tabs to connect to. Otherwise disconnect the port.
   if (lifelineTab == removedTabId) {
     if (dartTabs.isEmpty) {
       lifelineTab = null;
-      _debugLog('No more Dart tabs, disconnecting from lifeline port.');
+      debugLog('No more Dart tabs, disconnecting from lifeline port.');
       _disconnectFromLifelinePort();
     } else {
       lifelineTab = dartTabs.last;
-      _debugLog('Reconnecting lifeline port to a new Dart tab: $lifelineTab.');
+      debugLog('Reconnecting lifeline port to a new Dart tab: $lifelineTab.');
       _reconnectToLifelinePort();
     }
   }
@@ -75,45 +75,33 @@ void _keepLifelinePortAlive(Port port) {
   // Reconnect to the lifeline port every 5 minutes, as per:
   // https://bugs.chromium.org/p/chromium/issues/detail?id=1146434#c6
   Timer(Duration(minutes: 5), () {
-    _debugLog('5 minutes have elapsed, therefore reconnecting.');
+    debugLog('5 minutes have elapsed, therefore reconnecting.');
     _reconnectToLifelinePort();
   });
 }
 
 void _reconnectToLifelinePort() {
-  _debugLog('Reconnecting...');
+  debugLog('Reconnecting...');
   if (lifelinePort == null) {
-    _debugWarn('Could not find a lifeline port.');
+    debugWarn('Could not find a lifeline port.');
     return;
   }
   if (lifelineTab == null) {
-    _debugWarn('Could not find a lifeline tab.');
+    debugWarn('Could not find a lifeline tab.');
     return;
   }
   // Disconnect from the port, and then recreate the connection with the current
   // Dart tab:
   _disconnectFromLifelinePort();
   maybeCreateLifelinePort(lifelineTab!);
-  _debugLog('Reconnection complete.');
+  debugLog('Reconnection complete.');
 }
 
 void _disconnectFromLifelinePort() {
-  _debugLog('Disconnecting...');
+  debugLog('Disconnecting...');
   if (lifelinePort != null) {
     lifelinePort!.disconnect();
     lifelinePort = null;
-    _debugLog('Disconnection complete.');
-  }
-}
-
-void _debugLog(String msg) {
-  if (enableDebugLogging) {
-    console.log(msg);
-  }
-}
-
-void _debugWarn(String msg) {
-  if (enableDebugLogging) {
-    console.warn(msg);
+    debugLog('Disconnection complete.');
   }
 }
diff --git a/dwds/debug_extension_mv3/web/logger.dart b/dwds/debug_extension_mv3/web/logger.dart
new file mode 100644
index 000000000..a2dddb65d
--- /dev/null
+++ b/dwds/debug_extension_mv3/web/logger.dart
@@ -0,0 +1,47 @@
+// Copyright (c) 2022, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+@JS()
+library logger;
+
+import 'package:js/js.dart';
+
+import 'web_api.dart';
+
+// Switch to true for debug logging.
+bool _enableDebugLogging = true;
+
+enum _LogLevel {
+  info,
+  warn,
+  error,
+}
+
+debugLog(String msg, {String? prefix}) {
+  _log(msg, prefix: prefix);
+}
+
+debugWarn(String msg, {String? prefix}) {
+  _log(msg, prefix: prefix, level: _LogLevel.warn);
+}
+
+debugError(String msg, {String? prefix}) {
+  _log(msg, prefix: prefix, level: _LogLevel.error);
+}
+
+void _log(String msg, {_LogLevel? level, String? prefix}) {
+  if (!_enableDebugLogging) return;
+  final logMsg = prefix != null ? '[$prefix] $msg' : msg;
+  final logLevel = level ?? _LogLevel.info;
+  switch (logLevel) {
+    case _LogLevel.error:
+      console.error(logMsg);
+      break;
+    case _LogLevel.warn:
+      console.warn(logMsg);
+      break;
+    case _LogLevel.info:
+      console.log(logMsg);
+  }
+}
diff --git a/dwds/debug_extension_mv3/web/messaging.dart b/dwds/debug_extension_mv3/web/messaging.dart
index 4f4c1745b..8041e4ade 100644
--- a/dwds/debug_extension_mv3/web/messaging.dart
+++ b/dwds/debug_extension_mv3/web/messaging.dart
@@ -10,7 +10,7 @@ import 'dart:convert';
 import 'package:dwds/data/serializers.dart';
 import 'package:js/js.dart';
 
-import 'web_api.dart';
+import 'logger.dart';
 
 enum Script {
   background,
@@ -85,7 +85,7 @@ void interceptMessage<T>({
     messageHandler(
         serializers.deserialize(jsonDecode(decodedMessage.body)) as T);
   } catch (error) {
-    console.warn(
+    debugError(
         'Error intercepting $expectedType from $expectedSender to $expectedRecipient: $error');
   }
 }
diff --git a/dwds/debug_extension_mv3/web/storage.dart b/dwds/debug_extension_mv3/web/storage.dart
index a989e6310..dc4328ced 100644
--- a/dwds/debug_extension_mv3/web/storage.dart
+++ b/dwds/debug_extension_mv3/web/storage.dart
@@ -13,10 +13,7 @@ import 'package:js/js.dart';
 
 import 'chrome_api.dart';
 import 'data_serializers.dart';
-import 'web_api.dart';
-
-/// Switch to true for debug logging.
-bool enableDebugLogging = true;
+import 'logger.dart';
 
 enum StorageObject {
   debugInfo,
@@ -46,7 +43,7 @@ Future<bool> setStorageObject<T>({
     if (callback != null) {
       callback();
     }
-    _debugLog(storageKey, 'Set: $json');
+    debugLog('Set: $json', prefix: storageKey);
     completer.complete(true);
   }));
   return completer.future;
@@ -58,11 +55,11 @@ Future<T?> fetchStorageObject<T>({required StorageObject type, int? tabId}) {
   chrome.storage.local.get([storageKey], allowInterop((Object storageObj) {
     final json = getProperty(storageObj, storageKey) as String?;
     if (json == null) {
-      _debugWarn(storageKey, 'Does not exist.');
+      debugWarn('Does not exist.', prefix: storageKey);
       completer.complete(null);
     } else {
       final value = serializers.deserialize(jsonDecode(json)) as T;
-      _debugLog(storageKey, 'Fetched: $json');
+      debugLog('Fetched: $json', prefix: storageKey);
       completer.complete(value);
     }
   }));
@@ -73,15 +70,3 @@ String _createStorageKey(StorageObject type, int? tabId) {
   if (tabId == null) return type.keyName;
   return '$tabId-${type.keyName}';
 }
-
-void _debugLog(String storageKey, String msg) {
-  if (enableDebugLogging) {
-    console.log('[$storageKey] $msg');
-  }
-}
-
-void _debugWarn(String storageKey, String msg) {
-  if (enableDebugLogging) {
-    console.warn('[$storageKey] $msg');
-  }
-}
diff --git a/dwds/debug_extension_mv3/web/web_api.dart b/dwds/debug_extension_mv3/web/web_api.dart
index 6679af033..9bc8c3381 100644
--- a/dwds/debug_extension_mv3/web/web_api.dart
+++ b/dwds/debug_extension_mv3/web/web_api.dart
@@ -17,6 +17,9 @@ class Console {
 
   external void warn(String header,
       [String style1, String style2, String style3]);
+
+  external void error(String header,
+      [String style1, String style2, String style3]);
 }
 
 // Custom implementation of Fetch API until the Dart implementation supports

From 80427381b453b6cf6705707573e2cd6b132c2abc Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Mon, 28 Nov 2022 15:10:49 -0800
Subject: [PATCH 2/9] Getting back a DevTools URL

---
 dwds/debug_extension_mv3/pubspec.yaml         |   4 +
 dwds/debug_extension_mv3/web/background.dart  |   9 +-
 dwds/debug_extension_mv3/web/chrome_api.dart  |  44 +++
 .../web/data_serializers.dart                 |   8 +
 .../web/data_serializers.g.dart               |  10 +-
 .../web/debug_session.dart                    | 309 ++++++++++++++++++
 dwds/debug_extension_mv3/web/web_api.dart     |  11 +
 7 files changed, 389 insertions(+), 6 deletions(-)
 create mode 100644 dwds/debug_extension_mv3/web/debug_session.dart

diff --git a/dwds/debug_extension_mv3/pubspec.yaml b/dwds/debug_extension_mv3/pubspec.yaml
index 2e13fcba1..bb54e5596 100644
--- a/dwds/debug_extension_mv3/pubspec.yaml
+++ b/dwds/debug_extension_mv3/pubspec.yaml
@@ -10,11 +10,13 @@ environment:
 
 dependencies:
   built_value: ^8.3.0
+  collection: ^1.15.0
   js: ^0.6.1+1
 
 dev_dependencies:
   build: ^2.0.0
   build_runner: ^2.0.6
+  built_collection: ^5.0.0
   built_value_generator: ^8.3.0
   build_web_compilers: ^3.0.0
   dwds: ^16.0.0
@@ -22,3 +24,5 @@ dev_dependencies:
 dependency_overrides:
   dwds:
     path: ..
+  sse:
+    path: /Users/elliottbrooks/dev/sse
diff --git a/dwds/debug_extension_mv3/web/background.dart b/dwds/debug_extension_mv3/web/background.dart
index f1b853444..92d19c69a 100644
--- a/dwds/debug_extension_mv3/web/background.dart
+++ b/dwds/debug_extension_mv3/web/background.dart
@@ -12,8 +12,9 @@ import 'package:dwds/data/debug_info.dart';
 import 'package:dwds/data/extension_request.dart';
 import 'package:js/js.dart';
 
-import 'chrome_api.dart';
 import 'data_types.dart';
+import 'debug_session.dart';
+import 'chrome_api.dart';
 import 'lifeline_ports.dart';
 import 'logger.dart';
 import 'messaging.dart';
@@ -58,10 +59,8 @@ Future<void> _startDebugSession(Tab currentTab) async {
   if (!isAuthenticated) return;
 
   maybeCreateLifelinePort(currentTab.id);
-  final devToolsOpener = await fetchStorageObject<DevToolsOpener>(
-      type: StorageObject.devToolsOpener);
-  await _createTab('https://dart.dev/',
-      inNewWindow: devToolsOpener?.newWindow ?? false);
+  registerDebugEventListeners();
+  attachDebugger(tabId);
 }
 
 Future<bool> _authenticateUser(String extensionUrl, int tabId) async {
diff --git a/dwds/debug_extension_mv3/web/chrome_api.dart b/dwds/debug_extension_mv3/web/chrome_api.dart
index 14d4c368f..4f61c5ee5 100644
--- a/dwds/debug_extension_mv3/web/chrome_api.dart
+++ b/dwds/debug_extension_mv3/web/chrome_api.dart
@@ -11,6 +11,7 @@ external Chrome get chrome;
 @anonymous
 class Chrome {
   external Action get action;
+  external Debugger get debugger;
   external Notifications get notifications;
   external Runtime get runtime;
   external Scripting get scripting;
@@ -43,6 +44,39 @@ class IconInfo {
   external factory IconInfo({String path});
 }
 
+/// chrome.debugger APIs:
+/// https://developer.chrome.com/docs/extensions/reference/debugger
+
+@JS()
+@anonymous
+class Debugger {
+  external void attach(
+      Debuggee target, String requiredVersion, Function? callback);
+
+  external void detach(Debuggee target, Function? callback);
+
+  external void sendCommand(Debuggee target, String method,
+      Object? commandParams, Function? callback);
+
+  external OnEventHandler get onEvent;
+}
+
+@JS()
+@anonymous
+class OnEventHandler {
+  external void addListener(
+      void Function(Debuggee source, String method, Object? params) callback);
+}
+
+@JS()
+@anonymous
+class Debuggee {
+  external int get tabId;
+  external String get extensionId;
+  external String get targetId;
+  external factory Debuggee({int tabId, String? extensionId, String? targetId});
+}
+
 /// chrome.notification APIs:
 /// https://developer.chrome.com/docs/extensions/reference/notifications
 
@@ -75,11 +109,19 @@ class Runtime {
   external void sendMessage(
       String? id, Object? message, Object? options, Function? callback);
 
+  // Note: Not checking the lastError when one occurs throws a runtime exception.
+  external ChromeError? get lastError;
+
   external ConnectionHandler get onConnect;
 
   external OnMessageHandler get onMessage;
 }
 
+@JS()
+class ChromeError {
+  external String get message;
+}
+
 @JS()
 @anonymous
 class ConnectInfo {
@@ -177,6 +219,8 @@ class Tabs {
 
   external Object create(TabInfo tabInfo);
 
+  external Object get(int tabId);
+
   external OnActivatedHandler get onActivated;
 
   external OnRemovedHandler get onRemoved;
diff --git a/dwds/debug_extension_mv3/web/data_serializers.dart b/dwds/debug_extension_mv3/web/data_serializers.dart
index 20552e636..1cb6268ae 100644
--- a/dwds/debug_extension_mv3/web/data_serializers.dart
+++ b/dwds/debug_extension_mv3/web/data_serializers.dart
@@ -2,8 +2,11 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'package:built_collection/built_collection.dart';
 import 'package:built_value/serializer.dart';
 import 'package:dwds/data/debug_info.dart';
+import 'package:dwds/data/devtools_request.dart';
+import 'package:dwds/data/extension_request.dart';
 
 import 'data_types.dart';
 
@@ -11,7 +14,12 @@ part 'data_serializers.g.dart';
 
 /// Serializers for all the data types used in the Dart Debug Extension.
 @SerializersFor([
+  BatchedEvents,
   DebugInfo,
   DevToolsOpener,
+  DevToolsRequest,
+  ExtensionEvent,
+  ExtensionRequest,
+  ExtensionResponse,
 ])
 final Serializers serializers = _$serializers;
diff --git a/dwds/debug_extension_mv3/web/data_serializers.g.dart b/dwds/debug_extension_mv3/web/data_serializers.g.dart
index 2d11b95a2..5dc6bb9b1 100644
--- a/dwds/debug_extension_mv3/web/data_serializers.g.dart
+++ b/dwds/debug_extension_mv3/web/data_serializers.g.dart
@@ -7,8 +7,16 @@ part of 'data_serializers.dart';
 // **************************************************************************
 
 Serializers _$serializers = (new Serializers().toBuilder()
+      ..add(BatchedEvents.serializer)
       ..add(DebugInfo.serializer)
-      ..add(DevToolsOpener.serializer))
+      ..add(DevToolsOpener.serializer)
+      ..add(DevToolsRequest.serializer)
+      ..add(ExtensionEvent.serializer)
+      ..add(ExtensionRequest.serializer)
+      ..add(ExtensionResponse.serializer)
+      ..addBuilderFactory(
+          const FullType(BuiltList, const [const FullType(ExtensionEvent)]),
+          () => new ListBuilder<ExtensionEvent>()))
     .build();
 
 // ignore_for_file: always_put_control_body_on_new_line,always_specify_types,annotate_overrides,avoid_annotating_with_dynamic,avoid_as,avoid_catches_without_on_clauses,avoid_returning_this,deprecated_member_use_from_same_package,lines_longer_than_80_chars,no_leading_underscores_for_local_identifiers,omit_local_variable_types,prefer_expression_function_bodies,sort_constructors_first,test_types_in_equals,unnecessary_const,unnecessary_new,unnecessary_lambdas
diff --git a/dwds/debug_extension_mv3/web/debug_session.dart b/dwds/debug_extension_mv3/web/debug_session.dart
new file mode 100644
index 000000000..a85990917
--- /dev/null
+++ b/dwds/debug_extension_mv3/web/debug_session.dart
@@ -0,0 +1,309 @@
+// Copyright (c) 2022, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+@JS()
+library debugging;
+
+import 'dart:async';
+import 'dart:convert';
+import 'dart:html';
+import 'dart:js_util';
+
+import 'package:built_collection/built_collection.dart';
+import 'package:collection/collection.dart' show IterableExtension;
+import 'package:dwds/data/debug_info.dart';
+import 'package:dwds/data/devtools_request.dart';
+import 'package:dwds/data/extension_request.dart';
+import 'package:dwds/src/sockets.dart';
+// TODO(https://github.com/dart-lang/sdk/issues/49973): Use conditional imports
+// in .../utilities/batched_stream so that we don't need to import a copy.
+import 'package:dwds/src/web_utilities/batched_stream.dart';
+import 'package:js/js.dart';
+import 'package:js/js_util.dart' as js_util;
+import 'package:sse/client/sse_client.dart';
+import 'package:web_socket_channel/web_socket_channel.dart';
+import 'chrome_api.dart';
+import 'data_serializers.dart';
+import 'logger.dart';
+import 'storage.dart';
+import 'web_api.dart';
+
+bool _enableDebugLogging = const bool.fromEnvironment("is_dev");
+
+const _notADartAppAlert = 'No Dart application detected.'
+    ' Are you trying to debug an application that includes a Chrome hosted app'
+    ' (an application listed in chrome://apps)? If so, debugging is disabled.'
+    ' You can fix this by removing the application from chrome://apps. Please'
+    ' see https://bugs.chromium.org/p/chromium/issues/detail?id=885025#c11.';
+
+const _devToolsAlreadyOpenedAlert =
+    'DevTools is already opened on a different window.';
+
+final _debugSessions = <_DebugSession>[];
+
+void registerDebugEventListeners() {
+  chrome.debugger.onEvent.addListener(allowInterop(_onDebuggerEvent));
+}
+
+void attachDebugger(int tabId) {
+  chrome.debugger.attach(
+    Debuggee(tabId: tabId),
+    '1.3',
+    allowInterop(
+      () => _enableExecutionContextReporting(tabId),
+    ),
+  );
+}
+
+_enableExecutionContextReporting(int tabId) {
+  // Runtime.enable enables reporting of execution contexts creation by means of
+  // executionContextCreated event. When the reporting gets enabled the event
+  // will be sent immediately for each existing execution context:
+  chrome.debugger.sendCommand(
+      Debuggee(tabId: tabId), 'Runtime.enable', EmptyParam(), allowInterop((_) {
+    final chromeError = chrome.runtime.lastError;
+    if (chromeError != null) {
+      final errorMessage = _translateChromeError(chromeError.message);
+      chrome.notifications.create(/*notificationId*/ null,
+          NotificationOptions(message: errorMessage), /*callback*/ null);
+      return;
+    }
+  }));
+}
+
+String _translateChromeError(String chromeErrorMessage) {
+  if (chromeErrorMessage.contains('Cannot access') ||
+      chromeErrorMessage.contains('Cannot attach')) {
+    return _notADartAppAlert;
+  }
+  return _devToolsAlreadyOpenedAlert;
+}
+
+Future<void> _onDebuggerEvent(
+    Debuggee source, String method, Object? params) async {
+  if (method == 'Runtime.executionContextCreated') {
+    return _maybeConnectToDwds(source.tabId, params);
+  }
+
+  return _forwardChromeDebuggerEventToDwds(source, method, params);
+}
+
+Future<void> _maybeConnectToDwds(int tabId, Object? params) async {
+  final context = json.decode(JSON.stringify(params))['context'];
+  final contextOrigin = context['origin'] as String?;
+  if (contextOrigin == null) return;
+  if (contextOrigin.contains(('chrome-extension:'))) return;
+  final debugInfo = await fetchStorageObject<DebugInfo>(
+    type: StorageObject.debugInfo,
+    tabId: tabId,
+  );
+  if (debugInfo == null) return;
+  if (contextOrigin != debugInfo.appOrigin) return;
+  final contextId = context['id'] as int;
+  final connected = await _connectToDwds(
+    dartAppContextId: contextId,
+    dartAppTabId: tabId,
+    debugInfo: debugInfo,
+  );
+  if (!connected) {
+    debugWarn('Failed to connect to DWDS for $contextOrigin.');
+  }
+}
+
+Future<bool> _connectToDwds({
+  required int dartAppContextId,
+  required int dartAppTabId,
+  required DebugInfo debugInfo,
+}) async {
+  if (debugInfo.extensionUrl == null) {
+    debugWarn('Can\'t connect to DWDS without an extension URL.');
+    return false;
+  }
+  final uri = Uri.parse(debugInfo.extensionUrl!);
+  // Start the client connection with DWDS:
+  final client = uri.isScheme('ws') || uri.isScheme('wss')
+      ? WebSocketClient(WebSocketChannel.connect(uri))
+      : SseSocketClient(SseClient(uri.toString()));
+  final debugSession = _DebugSession(client: client, appTabId: dartAppTabId);
+  _debugSessions.add(debugSession);
+  client.stream.listen(
+    (data) => _routeDwdsEvent(data, client, dartAppTabId),
+    onDone: () {
+      debugLog('Shutting down DWDS communication channel.');
+      _removeAndDetachDebugSessionForTab(dartAppTabId);
+    },
+    onError: (err) {
+      debugWarn('Error in DWDS communication channel: $err');
+      _removeAndDetachDebugSessionForTab(dartAppTabId);
+    },
+    cancelOnError: true,
+  );
+  final tabUrl = await _getTabUrl(dartAppTabId);
+  // Send a DevtoolsRequest to the event stream:
+  final event = jsonEncode(serializers.serialize(DevToolsRequest((b) => b
+    ..appId = debugInfo.appId
+    ..instanceId = debugInfo.appInstanceId
+    ..contextId = dartAppContextId
+    ..tabUrl = tabUrl
+    ..uriOnly = true)));
+  client.sink.add(event);
+  return true;
+}
+
+void _routeDwdsEvent(String eventData, SocketClient client, int tabId) {
+  final message = serializers.deserialize(jsonDecode(eventData));
+  if (message is ExtensionRequest) {
+    _forwardDwdsEventToChromeDebugger(message, client, tabId);
+  } else if (message is ExtensionEvent) {
+    switch (message.method) {
+      case 'dwds.encodedUri':
+        // TODO(elliette): Forward to external extensions.
+        break;
+      case 'dwds.devtoolsUri':
+        debugLog('Received DevTools URL: ${message.params}');
+        break;
+    }
+  }
+}
+
+void _forwardDwdsEventToChromeDebugger(
+    ExtensionRequest message, SocketClient client, int tabId) {
+  final messageParams = message.commandParams ?? '{}';
+  final params = BuiltMap<String, Object>(json.decode(messageParams)).toMap();
+  chrome.debugger.sendCommand(
+      Debuggee(tabId: tabId), message.command, js_util.jsify(params),
+      allowInterop(([e]) {
+    // No arguments indicate that an error occurred.
+    if (e == null) {
+      client.sink
+          .add(jsonEncode(serializers.serialize(ExtensionResponse((b) => b
+            ..id = message.id
+            ..success = false
+            ..result = JSON.stringify(chrome.runtime.lastError)))));
+    } else {
+      client.sink
+          .add(jsonEncode(serializers.serialize(ExtensionResponse((b) => b
+            ..id = message.id
+            ..success = true
+            ..result = JSON.stringify(e)))));
+    }
+  }));
+}
+
+void _forwardChromeDebuggerEventToDwds(
+    Debuggee source, String method, dynamic params) {
+  final debugSession = _debugSessions
+      .firstWhereOrNull((session) => session.appTabId == source.tabId);
+
+  if (debugSession == null) return;
+
+  final event = _extensionEventFor(method, params);
+
+  if (method == 'Debugger.scriptParsed') {
+    debugSession.sendBatchedEvent(event);
+  } else {
+    debugSession.sendEvent(event);
+  }
+}
+
+// Tries to remove the debug session for the specified tab, and detach the
+// debugger associated with that debug session.
+void _removeAndDetachDebugSessionForTab(int tabId) {
+  final removedTabId = _removeDebugSessionForTab(tabId);
+
+  if (removedTabId != -1) {
+    chrome.debugger.detach(Debuggee(tabId: removedTabId), allowInterop(() {}));
+  }
+}
+
+// Tries to remove the debug session for the specified tab. If no session is
+// found, returns -1. Otherwise returns the tab ID.
+int _removeDebugSessionForTab(int tabId) {
+  final session =
+      _debugSessions.firstWhereOrNull((session) => session.appTabId == tabId);
+  if (session != null) {
+    // Note: package:sse will try to keep the connection alive, even after the
+    // client has been closed. Therefore the extension sends an event to notify
+    // DWDS that we should close the connection, instead of relying on the done
+    // event sent when the client is closed. See details:
+    // https://github.com/dart-lang/webdev/pull/1595#issuecomment-1116773378
+    final event =
+        _extensionEventFor('DebugExtension.detached', js_util.jsify({}));
+    session.sendEvent(event);
+    session.close();
+    _debugSessions.remove(session);
+    return session.appTabId;
+  } else {
+    return -1;
+  }
+}
+
+/// Construct an [ExtensionEvent] from [method] and [params].
+ExtensionEvent _extensionEventFor(String method, dynamic params) {
+  return ExtensionEvent((b) => b
+    ..params = jsonEncode(json.decode(JSON.stringify(params)))
+    ..method = jsonEncode(method));
+}
+
+Future<String> _getTabUrl(int tabId) async {
+  final tab = await promiseToFuture<Tab?>(chrome.tabs.get(tabId));
+  return tab?.url ?? '';
+}
+
+@JS()
+@anonymous
+class EmptyParam {
+  external factory EmptyParam();
+}
+
+class _DebugSession {
+  // The tab ID that contains the running Dart application.
+  final int appTabId;
+
+  // Socket client for communication with dwds extension backend.
+  late final SocketClient _socketClient;
+
+  // How often to send batched events.
+  static const int _batchDelayMilliseconds = 1000;
+
+  // Collect events into batches to be send periodically to the server.
+  final _batchController =
+      BatchedStreamController<ExtensionEvent>(delay: _batchDelayMilliseconds);
+  late final StreamSubscription<List<ExtensionEvent>> _batchSubscription;
+
+  _DebugSession({
+    required client,
+    required this.appTabId,
+  }) : _socketClient = client {
+    // Collect extension events and send them periodically to the server.
+    _batchSubscription = _batchController.stream.listen((events) {
+      _socketClient.sink.add(jsonEncode(serializers.serialize(BatchedEvents(
+          (b) => b.events = ListBuilder<ExtensionEvent>(events)))));
+    });
+  }
+
+  void set socketClient(SocketClient client) {
+    _socketClient = client;
+
+    // Collect extension events and send them periodically to the server.
+    _batchSubscription = _batchController.stream.listen((events) {
+      _socketClient.sink.add(jsonEncode(serializers.serialize(BatchedEvents(
+          (b) => b.events = ListBuilder<ExtensionEvent>(events)))));
+    });
+  }
+
+  void sendEvent(ExtensionEvent event) {
+    _socketClient.sink.add(jsonEncode(serializers.serialize(event)));
+  }
+
+  void sendBatchedEvent(ExtensionEvent event) {
+    _batchController.sink.add(event);
+  }
+
+  void close() {
+    _socketClient.close();
+    _batchSubscription.cancel();
+    _batchController.close();
+  }
+}
diff --git a/dwds/debug_extension_mv3/web/web_api.dart b/dwds/debug_extension_mv3/web/web_api.dart
index 9bc8c3381..b91e80c4f 100644
--- a/dwds/debug_extension_mv3/web/web_api.dart
+++ b/dwds/debug_extension_mv3/web/web_api.dart
@@ -9,6 +9,10 @@ import 'dart:js_util' as js_util;
 @JS()
 external Console get console;
 
+@JS()
+// ignore: non_constant_identifier_names
+external Json get JSON;
+
 @JS()
 @anonymous
 class Console {
@@ -22,6 +26,13 @@ class Console {
       [String style1, String style2, String style3]);
 }
 
+@JS()
+@anonymous
+class Json {
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify
+  external String stringify(o);
+}
+
 // Custom implementation of Fetch API until the Dart implementation supports
 // credentials. See https://github.com/dart-lang/http/issues/595.
 @JS('fetch')

From 9b57a3b4b0217102f8f5ab432cd7bf3463ee8f7c Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Mon, 28 Nov 2022 15:27:25 -0800
Subject: [PATCH 3/9] Can open DevTools

---
 dwds/debug_extension_mv3/web/background.dart  |  4 +--
 .../web/debug_session.dart                    | 16 ++++++++--
 dwds/debug_extension_mv3/web/tabs.dart        | 29 +++++++++++++++++++
 3 files changed, 44 insertions(+), 5 deletions(-)
 create mode 100644 dwds/debug_extension_mv3/web/tabs.dart

diff --git a/dwds/debug_extension_mv3/web/background.dart b/dwds/debug_extension_mv3/web/background.dart
index 92d19c69a..53caca037 100644
--- a/dwds/debug_extension_mv3/web/background.dart
+++ b/dwds/debug_extension_mv3/web/background.dart
@@ -12,13 +12,13 @@ import 'package:dwds/data/debug_info.dart';
 import 'package:dwds/data/extension_request.dart';
 import 'package:js/js.dart';
 
-import 'data_types.dart';
 import 'debug_session.dart';
 import 'chrome_api.dart';
 import 'lifeline_ports.dart';
 import 'logger.dart';
 import 'messaging.dart';
 import 'storage.dart';
+import 'tabs.dart';
 import 'web_api.dart';
 
 const _authSuccessResponse = 'Dart Debug Authentication Success!';
@@ -70,7 +70,7 @@ Future<bool> _authenticateUser(String extensionUrl, int tabId) async {
   if (!responseBody.contains(_authSuccessResponse)) {
     debugWarn('Not authenticated: ${response.status} / $responseBody');
     _showWarningNotification('Please re-authenticate and try again.');
-    await _createTab(authUrl, inNewWindow: false);
+    await createTab(authUrl, inNewWindow: false);
     return false;
   }
   return true;
diff --git a/dwds/debug_extension_mv3/web/debug_session.dart b/dwds/debug_extension_mv3/web/debug_session.dart
index a85990917..b90a71870 100644
--- a/dwds/debug_extension_mv3/web/debug_session.dart
+++ b/dwds/debug_extension_mv3/web/debug_session.dart
@@ -23,14 +23,14 @@ import 'package:js/js.dart';
 import 'package:js/js_util.dart' as js_util;
 import 'package:sse/client/sse_client.dart';
 import 'package:web_socket_channel/web_socket_channel.dart';
+import 'data_types.dart';
 import 'chrome_api.dart';
 import 'data_serializers.dart';
 import 'logger.dart';
 import 'storage.dart';
+import 'tabs.dart';
 import 'web_api.dart';
 
-bool _enableDebugLogging = const bool.fromEnvironment("is_dev");
-
 const _notADartAppAlert = 'No Dart application detected.'
     ' Are you trying to debug an application that includes a Chrome hosted app'
     ' (an application listed in chrome://apps)? If so, debugging is disabled.'
@@ -161,7 +161,7 @@ void _routeDwdsEvent(String eventData, SocketClient client, int tabId) {
         // TODO(elliette): Forward to external extensions.
         break;
       case 'dwds.devtoolsUri':
-        debugLog('Received DevTools URL: ${message.params}');
+        _openDevTools(message.params);
         break;
     }
   }
@@ -239,6 +239,16 @@ int _removeDebugSessionForTab(int tabId) {
   }
 }
 
+void _openDevTools(String devToolsUrl) async {
+  if (devToolsUrl.isEmpty) {
+    debugError('DevTools URL is empty.');
+    return;
+  }
+  final devToolsOpener = await fetchStorageObject<DevToolsOpener>(
+      type: StorageObject.devToolsOpener);
+  await createTab(devToolsUrl, inNewWindow: devToolsOpener?.newWindow ?? false);
+}
+
 /// Construct an [ExtensionEvent] from [method] and [params].
 ExtensionEvent _extensionEventFor(String method, dynamic params) {
   return ExtensionEvent((b) => b
diff --git a/dwds/debug_extension_mv3/web/tabs.dart b/dwds/debug_extension_mv3/web/tabs.dart
new file mode 100644
index 000000000..4883f5f50
--- /dev/null
+++ b/dwds/debug_extension_mv3/web/tabs.dart
@@ -0,0 +1,29 @@
+// Copyright (c) 2022, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+@JS()
+library tabs;
+
+import 'dart:async';
+import 'dart:html';
+
+import 'package:js/js.dart';
+
+import 'chrome_api.dart';
+
+
+Future<Tab> createTab(String url, {bool inNewWindow = false}) async {
+  if (inNewWindow) {
+    final windowPromise = chrome.windows.create(
+      WindowInfo(focused: true, url: url),
+    );
+    final windowObj = await promiseToFuture<WindowObj>(windowPromise);
+    return windowObj.tabs.first;
+  }
+  final tabPromise = chrome.tabs.create(TabInfo(
+    active: true,
+    url: url,
+  ));
+  return promiseToFuture<Tab>(tabPromise);
+}
\ No newline at end of file

From ddf9c34d115ab0b46510f920eeb235ceee11c968 Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Mon, 28 Nov 2022 17:09:49 -0800
Subject: [PATCH 4/9] Can detach debugger / close DevTools

---
 dwds/debug_extension_mv3/web/background.dart  |  15 --
 dwds/debug_extension_mv3/web/chrome_api.dart  |  11 ++
 .../web/debug_session.dart                    | 132 ++++++++++++------
 dwds/debug_extension_mv3/web/tabs.dart        |  13 +-
 4 files changed, 111 insertions(+), 60 deletions(-)

diff --git a/dwds/debug_extension_mv3/web/background.dart b/dwds/debug_extension_mv3/web/background.dart
index 53caca037..53ace219f 100644
--- a/dwds/debug_extension_mv3/web/background.dart
+++ b/dwds/debug_extension_mv3/web/background.dart
@@ -155,18 +155,3 @@ Future<Tab?> _getTab() async {
   final tabs = List<Tab>.from(await promiseToFuture(chrome.tabs.query(query)));
   return tabs.isNotEmpty ? tabs.first : null;
 }
-
-Future<Tab> _createTab(String url, {bool inNewWindow = false}) async {
-  if (inNewWindow) {
-    final windowPromise = chrome.windows.create(
-      WindowInfo(focused: true, url: url),
-    );
-    final windowObj = await promiseToFuture<WindowObj>(windowPromise);
-    return windowObj.tabs.first;
-  }
-  final tabPromise = chrome.tabs.create(TabInfo(
-    active: true,
-    url: url,
-  ));
-  return promiseToFuture<Tab>(tabPromise);
-}
diff --git a/dwds/debug_extension_mv3/web/chrome_api.dart b/dwds/debug_extension_mv3/web/chrome_api.dart
index 4f61c5ee5..ee115777e 100644
--- a/dwds/debug_extension_mv3/web/chrome_api.dart
+++ b/dwds/debug_extension_mv3/web/chrome_api.dart
@@ -58,9 +58,18 @@ class Debugger {
   external void sendCommand(Debuggee target, String method,
       Object? commandParams, Function? callback);
 
+  external OnDetachHandler get onDetach;
+
   external OnEventHandler get onEvent;
 }
 
+@JS()
+@anonymous
+class OnDetachHandler {
+  external void addListener(
+      void Function(Debuggee source, String reason) callback);
+}
+
 @JS()
 @anonymous
 class OnEventHandler {
@@ -221,6 +230,8 @@ class Tabs {
 
   external Object get(int tabId);
 
+  external Object remove(int tabId);
+
   external OnActivatedHandler get onActivated;
 
   external OnRemovedHandler get onRemoved;
diff --git a/dwds/debug_extension_mv3/web/debug_session.dart b/dwds/debug_extension_mv3/web/debug_session.dart
index b90a71870..f2642f238 100644
--- a/dwds/debug_extension_mv3/web/debug_session.dart
+++ b/dwds/debug_extension_mv3/web/debug_session.dart
@@ -3,12 +3,10 @@
 // BSD-style license that can be found in the LICENSE file.
 
 @JS()
-library debugging;
+library debug_session;
 
 import 'dart:async';
 import 'dart:convert';
-import 'dart:html';
-import 'dart:js_util';
 
 import 'package:built_collection/built_collection.dart';
 import 'package:collection/collection.dart' show IterableExtension;
@@ -23,9 +21,10 @@ import 'package:js/js.dart';
 import 'package:js/js_util.dart' as js_util;
 import 'package:sse/client/sse_client.dart';
 import 'package:web_socket_channel/web_socket_channel.dart';
-import 'data_types.dart';
+
 import 'chrome_api.dart';
 import 'data_serializers.dart';
+import 'data_types.dart';
 import 'logger.dart';
 import 'storage.dart';
 import 'tabs.dart';
@@ -42,8 +41,17 @@ const _devToolsAlreadyOpenedAlert =
 
 final _debugSessions = <_DebugSession>[];
 
+enum TabType {
+  dartApp,
+  devTools,
+}
+
 void registerDebugEventListeners() {
   chrome.debugger.onEvent.addListener(allowInterop(_onDebuggerEvent));
+  chrome.debugger.onDetach.addListener(allowInterop(_handleDebuggerDetach));
+  chrome.tabs.onRemoved.addListener(allowInterop(
+    (tabId, _) => _detachDebuggerForTab(tabId, type: TabType.devTools),
+  ));
 }
 
 void attachDebugger(int tabId) {
@@ -131,11 +139,11 @@ Future<bool> _connectToDwds({
     (data) => _routeDwdsEvent(data, client, dartAppTabId),
     onDone: () {
       debugLog('Shutting down DWDS communication channel.');
-      _removeAndDetachDebugSessionForTab(dartAppTabId);
+      _detachDebuggerForTab(dartAppTabId, type: TabType.dartApp);
     },
     onError: (err) {
       debugWarn('Error in DWDS communication channel: $err');
-      _removeAndDetachDebugSessionForTab(dartAppTabId);
+      _detachDebuggerForTab(dartAppTabId, type: TabType.dartApp);
     },
     cancelOnError: true,
   );
@@ -161,7 +169,7 @@ void _routeDwdsEvent(String eventData, SocketClient client, int tabId) {
         // TODO(elliette): Forward to external extensions.
         break;
       case 'dwds.devtoolsUri':
-        _openDevTools(message.params);
+        _openDevTools(message.params, dartTabId: tabId);
         break;
     }
   }
@@ -195,11 +203,8 @@ void _forwardChromeDebuggerEventToDwds(
     Debuggee source, String method, dynamic params) {
   final debugSession = _debugSessions
       .firstWhereOrNull((session) => session.appTabId == source.tabId);
-
   if (debugSession == null) return;
-
   final event = _extensionEventFor(method, params);
-
   if (method == 'Debugger.scriptParsed') {
     debugSession.sendBatchedEvent(event);
   } else {
@@ -207,46 +212,76 @@ void _forwardChromeDebuggerEventToDwds(
   }
 }
 
-// Tries to remove the debug session for the specified tab, and detach the
-// debugger associated with that debug session.
-void _removeAndDetachDebugSessionForTab(int tabId) {
-  final removedTabId = _removeDebugSessionForTab(tabId);
+void _openDevTools(String devToolsUrl, {required int dartTabId}) async {
+  if (devToolsUrl.isEmpty) {
+    debugError('DevTools URL is empty.');
+    return;
+  }
+  final debugSession = _debugSessionForTab(dartTabId, type: TabType.dartApp);
+  if (debugSession == null) {
+    debugError('Debug session not found.');
+    return;
+  }
+  final devToolsOpener = await fetchStorageObject<DevToolsOpener>(
+      type: StorageObject.devToolsOpener);
+  final devToolsTab = await createTab(
+    devToolsUrl,
+    inNewWindow: devToolsOpener?.newWindow ?? false,
+  );
+  debugSession.devToolsTabId = devToolsTab.id;
+}
+
+void _detachDebuggerForTab(int tabId, {required TabType type}) {
+  final debugSession = _debugSessionForTab(tabId, type: type);
+  if (debugSession == null) return;
+  chrome.debugger.detach(Debuggee(tabId: debugSession.appTabId),
+      allowInterop(() {
+    final error = chrome.runtime.lastError;
+    if (error != null) {
+      debugWarn('Error detaching tab: ${error.message}');
+    } else {
+      debugLog('Detached debugger for ${debugSession.appTabId}');
+    }
+  }));
+}
 
-  if (removedTabId != -1) {
-    chrome.debugger.detach(Debuggee(tabId: removedTabId), allowInterop(() {}));
+void _handleDebuggerDetach(Debuggee source, String _) async {
+  final debugSession = _debugSessionForTab(source.tabId, type: TabType.dartApp);
+  if (debugSession == null) return;
+  _removeDebugSession(debugSession);
+  // Maybe close the associated DevTools tab as well:
+  final devToolsTabId = debugSession.devToolsTabId;
+  final devToolsTab = await getTab(devToolsTabId);
+  if (devToolsTab != null) {
+    chrome.tabs.remove(devToolsTabId);
   }
 }
 
-// Tries to remove the debug session for the specified tab. If no session is
-// found, returns -1. Otherwise returns the tab ID.
-int _removeDebugSessionForTab(int tabId) {
-  final session =
-      _debugSessions.firstWhereOrNull((session) => session.appTabId == tabId);
-  if (session != null) {
-    // Note: package:sse will try to keep the connection alive, even after the
-    // client has been closed. Therefore the extension sends an event to notify
-    // DWDS that we should close the connection, instead of relying on the done
-    // event sent when the client is closed. See details:
-    // https://github.com/dart-lang/webdev/pull/1595#issuecomment-1116773378
-    final event =
-        _extensionEventFor('DebugExtension.detached', js_util.jsify({}));
-    session.sendEvent(event);
-    session.close();
-    _debugSessions.remove(session);
-    return session.appTabId;
-  } else {
-    return -1;
+void _removeDebugSession(_DebugSession debugSession) {
+  // Note: package:sse will try to keep the connection alive, even after the
+  // client has been closed. Therefore the extension sends an event to notify
+  // DWDS that we should close the connection, instead of relying on the done
+  // event sent when the client is closed. See details:
+  // https://github.com/dart-lang/webdev/pull/1595#issuecomment-1116773378
+  final event =
+      _extensionEventFor('DebugExtension.detached', js_util.jsify({}));
+  debugSession.sendEvent(event);
+  debugSession.close();
+  final removed = _debugSessions.remove(debugSession);
+  if (!removed) {
+    debugWarn('Could not remove debug session.');
   }
 }
 
-void _openDevTools(String devToolsUrl) async {
-  if (devToolsUrl.isEmpty) {
-    debugError('DevTools URL is empty.');
-    return;
+_DebugSession? _debugSessionForTab(tabId, {required TabType type}) {
+  switch (type) {
+    case TabType.dartApp:
+      return _debugSessions
+          .firstWhereOrNull((session) => session.appTabId == tabId);
+    case TabType.devTools:
+      return _debugSessions
+          .firstWhereOrNull((session) => session.devToolsTabId == tabId);
   }
-  final devToolsOpener = await fetchStorageObject<DevToolsOpener>(
-      type: StorageObject.devToolsOpener);
-  await createTab(devToolsUrl, inNewWindow: devToolsOpener?.newWindow ?? false);
 }
 
 /// Construct an [ExtensionEvent] from [method] and [params].
@@ -257,7 +292,7 @@ ExtensionEvent _extensionEventFor(String method, dynamic params) {
 }
 
 Future<String> _getTabUrl(int tabId) async {
-  final tab = await promiseToFuture<Tab?>(chrome.tabs.get(tabId));
+  final tab = await getTab(tabId);
   return tab?.url ?? '';
 }
 
@@ -271,6 +306,9 @@ class _DebugSession {
   // The tab ID that contains the running Dart application.
   final int appTabId;
 
+  // The tab ID that contains the corresponding Dart DevTools.
+  late final int _devToolsTabId;
+
   // Socket client for communication with dwds extension backend.
   late final SocketClient _socketClient;
 
@@ -303,6 +341,14 @@ class _DebugSession {
     });
   }
 
+  int get devToolsTabId {
+    return _devToolsTabId;
+  }
+
+  void set devToolsTabId(int tabId) {
+    _devToolsTabId = tabId;
+  }
+
   void sendEvent(ExtensionEvent event) {
     _socketClient.sink.add(jsonEncode(serializers.serialize(event)));
   }
diff --git a/dwds/debug_extension_mv3/web/tabs.dart b/dwds/debug_extension_mv3/web/tabs.dart
index 4883f5f50..a880a7b70 100644
--- a/dwds/debug_extension_mv3/web/tabs.dart
+++ b/dwds/debug_extension_mv3/web/tabs.dart
@@ -12,7 +12,6 @@ import 'package:js/js.dart';
 
 import 'chrome_api.dart';
 
-
 Future<Tab> createTab(String url, {bool inNewWindow = false}) async {
   if (inNewWindow) {
     final windowPromise = chrome.windows.create(
@@ -26,4 +25,14 @@ Future<Tab> createTab(String url, {bool inNewWindow = false}) async {
     url: url,
   ));
   return promiseToFuture<Tab>(tabPromise);
-}
\ No newline at end of file
+}
+
+Future<Tab?> getTab(int tabId) {
+  return promiseToFuture<Tab?>(chrome.tabs.get(tabId));
+}
+
+Future<Tab?> getActiveTab() async {
+  final query = QueryInfo(active: true, currentWindow: true);
+  final tabs = List<Tab>.from(await promiseToFuture(chrome.tabs.query(query)));
+  return tabs.isNotEmpty ? tabs.first : null;
+}

From 6f4682cae0cce6a2434b62e8d24534e4a0909dd7 Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Tue, 29 Nov 2022 13:53:23 -0800
Subject: [PATCH 5/9] Rename tabs as utils

---
 dwds/debug_extension_mv3/web/background.dart           | 2 +-
 dwds/debug_extension_mv3/web/debug_session.dart        | 2 +-
 dwds/debug_extension_mv3/web/{tabs.dart => utils.dart} | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)
 rename dwds/debug_extension_mv3/web/{tabs.dart => utils.dart} (98%)

diff --git a/dwds/debug_extension_mv3/web/background.dart b/dwds/debug_extension_mv3/web/background.dart
index 53ace219f..05ecfb738 100644
--- a/dwds/debug_extension_mv3/web/background.dart
+++ b/dwds/debug_extension_mv3/web/background.dart
@@ -18,7 +18,7 @@ import 'lifeline_ports.dart';
 import 'logger.dart';
 import 'messaging.dart';
 import 'storage.dart';
-import 'tabs.dart';
+import 'utils.dart';
 import 'web_api.dart';
 
 const _authSuccessResponse = 'Dart Debug Authentication Success!';
diff --git a/dwds/debug_extension_mv3/web/debug_session.dart b/dwds/debug_extension_mv3/web/debug_session.dart
index f2642f238..81441ed6e 100644
--- a/dwds/debug_extension_mv3/web/debug_session.dart
+++ b/dwds/debug_extension_mv3/web/debug_session.dart
@@ -27,7 +27,7 @@ import 'data_serializers.dart';
 import 'data_types.dart';
 import 'logger.dart';
 import 'storage.dart';
-import 'tabs.dart';
+import 'utils.dart';
 import 'web_api.dart';
 
 const _notADartAppAlert = 'No Dart application detected.'
diff --git a/dwds/debug_extension_mv3/web/tabs.dart b/dwds/debug_extension_mv3/web/utils.dart
similarity index 98%
rename from dwds/debug_extension_mv3/web/tabs.dart
rename to dwds/debug_extension_mv3/web/utils.dart
index a880a7b70..590d2c38e 100644
--- a/dwds/debug_extension_mv3/web/tabs.dart
+++ b/dwds/debug_extension_mv3/web/utils.dart
@@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 @JS()
-library tabs;
+library utils;
 
 import 'dart:async';
 import 'dart:html';

From 51caa6ecdad6bdf67d4e3bc082aee8763a98006b Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Tue, 29 Nov 2022 14:23:46 -0800
Subject: [PATCH 6/9] Wip

---
 dwds/test/fixtures/context.dart         |  2 +-
 dwds/test/puppeteer/extension_test.dart | 12 +++--
 dwds/test/puppeteer/test_server.dart    | 67 +++++++++++++++++++++++++
 3 files changed, 76 insertions(+), 5 deletions(-)
 create mode 100644 dwds/test/puppeteer/test_server.dart

diff --git a/dwds/test/fixtures/context.dart b/dwds/test/fixtures/context.dart
index 7c0562665..f7e429d58 100644
--- a/dwds/test/fixtures/context.dart
+++ b/dwds/test/fixtures/context.dart
@@ -167,7 +167,7 @@ class TestContext {
 
     try {
       DartUri.currentDirectory = workingDirectory;
-      configureLogWriter();
+      // configureLogWriter();
 
       _client = IOClient(HttpClient()
         ..maxConnectionsPerHost = 200
diff --git a/dwds/test/puppeteer/extension_test.dart b/dwds/test/puppeteer/extension_test.dart
index ad1920a94..396711872 100644
--- a/dwds/test/puppeteer/extension_test.dart
+++ b/dwds/test/puppeteer/extension_test.dart
@@ -86,6 +86,7 @@ void main() async {
           expect(debugInfo.appInstanceId, isNotNull);
           expect(debugInfo.appOrigin, isNotNull);
           expect(debugInfo.appUrl, isNotNull);
+          print('EXTENSION URL ${debugInfo.extensionUrl}');
           await appTab.close();
         });
 
@@ -94,9 +95,9 @@ void main() async {
             () async {
           final appUrl = context.appUrl;
           // TODO(elliette): Replace with the DevTools url.
-          final devToolsUrl = 'https://dart.dev/';
+          final devToolsUrlFragment = useSse ? 'uri=sse' : 'uri=ws';
           final windowIdForAppJs = _windowIdForTabJs(appUrl);
-          final windowIdForDevToolsJs = _windowIdForTabJs(devToolsUrl);
+          // final windowIdForDevToolsJs = _windowIdForTabJs(devToolsUrlFragment);
           // Navigate to the Dart app:
           final appTab =
               await navigateToPage(browser, url: appUrl, isNew: true);
@@ -106,7 +107,10 @@ void main() async {
           await worker.evaluate(clickIconJs);
           // Verify the extension opened the Dart docs in the same window:
           var devToolsTabTarget = await browser
-              .waitForTarget((target) => target.url.contains(devToolsUrl));
+              .waitForTarget((target) => target.url.contains(devToolsUrlFragment));
+          final devToolsPage = await devToolsTabTarget.page;
+          print('URL IS: ${devToolsPage.url}');
+          final windowIdForDevToolsJs = _windowIdForTabJs(devToolsPage.url!);
           var devToolsWindowId =
               (await worker.evaluate(windowIdForDevToolsJs)) as int?;
           var appWindowId = (await worker.evaluate(windowIdForAppJs)) as int?;
@@ -134,7 +138,7 @@ void main() async {
           await worker.evaluate(clickIconJs);
           // Verify the extension opened DevTools in a different window:
           devToolsTabTarget = await browser
-              .waitForTarget((target) => target.url.contains(devToolsUrl));
+              .waitForTarget((target) => target.url.contains(devToolsUrlFragment));
           devToolsWindowId =
               (await worker.evaluate(windowIdForDevToolsJs)) as int?;
           appWindowId = (await worker.evaluate(windowIdForAppJs)) as int?;
diff --git a/dwds/test/puppeteer/test_server.dart b/dwds/test/puppeteer/test_server.dart
new file mode 100644
index 000000000..1e0fd2770
--- /dev/null
+++ b/dwds/test/puppeteer/test_server.dart
@@ -0,0 +1,67 @@
+// Copyright (c) 2022, the Dart project authors.  Please see the AUTHORS file
+// for details. 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:io';
+
+import 'package:args/args.dart';
+import 'package:path/path.dart' as p;
+
+import '../fixtures/context.dart';
+
+const useSseFlagName = 'use-sse';
+
+void main(List<String> arguments) async {
+  exitCode = 0; // presume success
+
+  // Parse command-line arguments:
+  final parser = ArgParser()
+    ..addFlag(
+      useSseFlagName,
+      negatable: true,
+      defaultsTo: false,
+      abbr: 's',
+    );
+  final argResults = parser.parse(arguments);
+  final useSse = argResults[useSseFlagName] as bool;
+
+  // Build the Dart Debug Extension:
+  print('Building Dart Debug Extension...');
+  final currentDir = Directory.current;
+  final extensionDir = absoluteWebdevPath(
+      currentPath: currentDir.path,
+      relativeWebdevPath: 'dwds/debug_extension_mv3');
+  await Process.run(
+    'tool/build_extension.sh',
+    [],
+    workingDirectory: extensionDir,
+  );
+
+  // Create a test context to launch the test server:
+  print('Starting a test server...');
+  final context = TestContext(
+    directory: absoluteWebdevPath(
+      currentPath: currentDir.path,
+      relativeWebdevPath: 'fixtures/_test',
+    ),
+    entry: absoluteWebdevPath(
+      currentPath: currentDir.path,
+      relativeWebdevPath: 'fixtures/_test/example/append_body/main.dart',
+    ),
+  );
+  await context.setUp(serveDevTools: true, useSse: useSse, launchChrome: false, enableDebugExtension: true);
+  final appUrl = context.appUrl;
+
+  print('============================================================');
+  print('APP IS RUNNING AT: $appUrl');
+}
+
+String absoluteWebdevPath(
+    {required String currentPath, required String relativeWebdevPath}) {
+  final currentPathParts = p.split(currentPath);
+  final pathPartsToWebdev =
+      currentPathParts.sublist(0, currentPathParts.indexOf('webdev') + 1);
+  final relativePathParts = p.split(relativeWebdevPath);
+  final pathToDir = p.joinAll([...pathPartsToWebdev, ...relativePathParts]);
+  return pathToDir;
+}
\ No newline at end of file

From bf385a2e65d12c6ea96ff1c00a959c41f4b0c3f5 Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Tue, 29 Nov 2022 15:24:44 -0800
Subject: [PATCH 7/9] Added test

---
 dwds/test/fixtures/context.dart         |  2 +-
 dwds/test/puppeteer/extension_test.dart | 14 +++---
 dwds/test/puppeteer/test_server.dart    | 67 -------------------------
 3 files changed, 8 insertions(+), 75 deletions(-)
 delete mode 100644 dwds/test/puppeteer/test_server.dart

diff --git a/dwds/test/fixtures/context.dart b/dwds/test/fixtures/context.dart
index f7e429d58..7c0562665 100644
--- a/dwds/test/fixtures/context.dart
+++ b/dwds/test/fixtures/context.dart
@@ -167,7 +167,7 @@ class TestContext {
 
     try {
       DartUri.currentDirectory = workingDirectory;
-      // configureLogWriter();
+      configureLogWriter();
 
       _client = IOClient(HttpClient()
         ..maxConnectionsPerHost = 200
diff --git a/dwds/test/puppeteer/extension_test.dart b/dwds/test/puppeteer/extension_test.dart
index 396711872..4c6654b86 100644
--- a/dwds/test/puppeteer/extension_test.dart
+++ b/dwds/test/puppeteer/extension_test.dart
@@ -42,6 +42,7 @@ void main() async {
           // TODO(elliette): Only start a TestServer, that way we can get rid of
           // the launchChrome parameter: https://github.com/dart-lang/webdev/issues/1779
           await context.setUp(
+            serveDevTools: true,
             launchChrome: false,
             useSse: useSse,
             enableDebugExtension: true,
@@ -86,7 +87,6 @@ void main() async {
           expect(debugInfo.appInstanceId, isNotNull);
           expect(debugInfo.appOrigin, isNotNull);
           expect(debugInfo.appUrl, isNotNull);
-          print('EXTENSION URL ${debugInfo.extensionUrl}');
           await appTab.close();
         });
 
@@ -95,7 +95,8 @@ void main() async {
             () async {
           final appUrl = context.appUrl;
           // TODO(elliette): Replace with the DevTools url.
-          final devToolsUrlFragment = useSse ? 'uri=sse' : 'uri=ws';
+          final devToolsUrlFragment =
+              useSse ? 'debugger?uri=sse' : 'debugger?uri=ws';
           final windowIdForAppJs = _windowIdForTabJs(appUrl);
           // final windowIdForDevToolsJs = _windowIdForTabJs(devToolsUrlFragment);
           // Navigate to the Dart app:
@@ -106,10 +107,9 @@ void main() async {
           await Future.delayed(Duration(seconds: executionContextDelay));
           await worker.evaluate(clickIconJs);
           // Verify the extension opened the Dart docs in the same window:
-          var devToolsTabTarget = await browser
-              .waitForTarget((target) => target.url.contains(devToolsUrlFragment));
+          var devToolsTabTarget = await browser.waitForTarget(
+              (target) => target.url.contains(devToolsUrlFragment));
           final devToolsPage = await devToolsTabTarget.page;
-          print('URL IS: ${devToolsPage.url}');
           final windowIdForDevToolsJs = _windowIdForTabJs(devToolsPage.url!);
           var devToolsWindowId =
               (await worker.evaluate(windowIdForDevToolsJs)) as int?;
@@ -137,8 +137,8 @@ void main() async {
           // Click on the Dart Debug Extension icon:
           await worker.evaluate(clickIconJs);
           // Verify the extension opened DevTools in a different window:
-          devToolsTabTarget = await browser
-              .waitForTarget((target) => target.url.contains(devToolsUrlFragment));
+          devToolsTabTarget = await browser.waitForTarget(
+              (target) => target.url.contains(devToolsUrlFragment));
           devToolsWindowId =
               (await worker.evaluate(windowIdForDevToolsJs)) as int?;
           appWindowId = (await worker.evaluate(windowIdForAppJs)) as int?;
diff --git a/dwds/test/puppeteer/test_server.dart b/dwds/test/puppeteer/test_server.dart
deleted file mode 100644
index 1e0fd2770..000000000
--- a/dwds/test/puppeteer/test_server.dart
+++ /dev/null
@@ -1,67 +0,0 @@
-// Copyright (c) 2022, the Dart project authors.  Please see the AUTHORS file
-// for details. 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:io';
-
-import 'package:args/args.dart';
-import 'package:path/path.dart' as p;
-
-import '../fixtures/context.dart';
-
-const useSseFlagName = 'use-sse';
-
-void main(List<String> arguments) async {
-  exitCode = 0; // presume success
-
-  // Parse command-line arguments:
-  final parser = ArgParser()
-    ..addFlag(
-      useSseFlagName,
-      negatable: true,
-      defaultsTo: false,
-      abbr: 's',
-    );
-  final argResults = parser.parse(arguments);
-  final useSse = argResults[useSseFlagName] as bool;
-
-  // Build the Dart Debug Extension:
-  print('Building Dart Debug Extension...');
-  final currentDir = Directory.current;
-  final extensionDir = absoluteWebdevPath(
-      currentPath: currentDir.path,
-      relativeWebdevPath: 'dwds/debug_extension_mv3');
-  await Process.run(
-    'tool/build_extension.sh',
-    [],
-    workingDirectory: extensionDir,
-  );
-
-  // Create a test context to launch the test server:
-  print('Starting a test server...');
-  final context = TestContext(
-    directory: absoluteWebdevPath(
-      currentPath: currentDir.path,
-      relativeWebdevPath: 'fixtures/_test',
-    ),
-    entry: absoluteWebdevPath(
-      currentPath: currentDir.path,
-      relativeWebdevPath: 'fixtures/_test/example/append_body/main.dart',
-    ),
-  );
-  await context.setUp(serveDevTools: true, useSse: useSse, launchChrome: false, enableDebugExtension: true);
-  final appUrl = context.appUrl;
-
-  print('============================================================');
-  print('APP IS RUNNING AT: $appUrl');
-}
-
-String absoluteWebdevPath(
-    {required String currentPath, required String relativeWebdevPath}) {
-  final currentPathParts = p.split(currentPath);
-  final pathPartsToWebdev =
-      currentPathParts.sublist(0, currentPathParts.indexOf('webdev') + 1);
-  final relativePathParts = p.split(relativeWebdevPath);
-  final pathToDir = p.joinAll([...pathPartsToWebdev, ...relativePathParts]);
-  return pathToDir;
-}
\ No newline at end of file

From e23274efa1a060b3cbb23c1f4b4026adc8fe44e4 Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Tue, 29 Nov 2022 15:35:36 -0800
Subject: [PATCH 8/9] Clean up

---
 dwds/debug_extension_mv3/pubspec.yaml   | 1 +
 dwds/test/puppeteer/extension_test.dart | 2 --
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/dwds/debug_extension_mv3/pubspec.yaml b/dwds/debug_extension_mv3/pubspec.yaml
index bb54e5596..b9bb88a3a 100644
--- a/dwds/debug_extension_mv3/pubspec.yaml
+++ b/dwds/debug_extension_mv3/pubspec.yaml
@@ -24,5 +24,6 @@ dev_dependencies:
 dependency_overrides:
   dwds:
     path: ..
+  # TODO(elliette): Remove override once package:sse is published.
   sse:
     path: /Users/elliottbrooks/dev/sse
diff --git a/dwds/test/puppeteer/extension_test.dart b/dwds/test/puppeteer/extension_test.dart
index 4c6654b86..ae243c741 100644
--- a/dwds/test/puppeteer/extension_test.dart
+++ b/dwds/test/puppeteer/extension_test.dart
@@ -94,11 +94,9 @@ void main() async {
             'can configure opening DevTools in a tab/window with extension settings',
             () async {
           final appUrl = context.appUrl;
-          // TODO(elliette): Replace with the DevTools url.
           final devToolsUrlFragment =
               useSse ? 'debugger?uri=sse' : 'debugger?uri=ws';
           final windowIdForAppJs = _windowIdForTabJs(appUrl);
-          // final windowIdForDevToolsJs = _windowIdForTabJs(devToolsUrlFragment);
           // Navigate to the Dart app:
           final appTab =
               await navigateToPage(browser, url: appUrl, isNew: true);

From 3978d44787a1b85a7018c0d4a281bf74db9fe609 Mon Sep 17 00:00:00 2001
From: Elliott Brooks <21270878+elliette@users.noreply.github.com>
Date: Tue, 29 Nov 2022 16:20:55 -0800
Subject: [PATCH 9/9] fix analyzer errors

---
 dwds/debug_extension_mv3/web/debug_session.dart | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/dwds/debug_extension_mv3/web/debug_session.dart b/dwds/debug_extension_mv3/web/debug_session.dart
index 81441ed6e..b7f4c61d6 100644
--- a/dwds/debug_extension_mv3/web/debug_session.dart
+++ b/dwds/debug_extension_mv3/web/debug_session.dart
@@ -307,7 +307,7 @@ class _DebugSession {
   final int appTabId;
 
   // The tab ID that contains the corresponding Dart DevTools.
-  late final int _devToolsTabId;
+  late final int devToolsTabId;
 
   // Socket client for communication with dwds extension backend.
   late final SocketClient _socketClient;
@@ -331,7 +331,7 @@ class _DebugSession {
     });
   }
 
-  void set socketClient(SocketClient client) {
+  set socketClient(SocketClient client) {
     _socketClient = client;
 
     // Collect extension events and send them periodically to the server.
@@ -341,14 +341,6 @@ class _DebugSession {
     });
   }
 
-  int get devToolsTabId {
-    return _devToolsTabId;
-  }
-
-  void set devToolsTabId(int tabId) {
-    _devToolsTabId = tabId;
-  }
-
   void sendEvent(ExtensionEvent event) {
     _socketClient.sink.add(jsonEncode(serializers.serialize(event)));
   }