Run dcm check-unused-code on the devtools_extensions package (#9933)

diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
index ed990d4..d5f3f2e 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml

@@ -86,7 +86,7 @@
       - name: Run dcm checks on packages
         # TODO(https://github.com/flutter/devtools/issues/9906): run on all DevTools packages.
         run: |
-          dcm check-unused-code packages/devtools_app packages/devtools_shared --exclude-public-api
+          dcm check-unused-code packages/devtools_app packages/devtools_extensions packages/devtools_shared --exclude-public-api
 
   test-packages:
     name: ${{ matrix.os }} ${{ matrix.package }} test

diff --git a/packages/devtools_extensions/integration_test/test/simulated_environment_test.dart b/packages/devtools_extensions/integration_test/test/simulated_environment_test.dart
index 4e155ca..7c50f4b 100644
--- a/packages/devtools_extensions/integration_test/test/simulated_environment_test.dart
+++ b/packages/devtools_extensions/integration_test/test/simulated_environment_test.dart

@@ -15,7 +15,6 @@
 // dart run integration_test/run_tests.dart --target=integration_test/test/simulated_environment_test.dart
 
 const safePumpDuration = Duration(seconds: 3);
-const longPumpDuration = Duration(seconds: 6);
 
 void main() {
   IntegrationTestWidgetsFlutterBinding.ensureInitialized();

diff --git a/packages/devtools_extensions/lib/src/template/_simulated_devtools_environment/connection_ui/_connect.dart b/packages/devtools_extensions/lib/src/template/_simulated_devtools_environment/connection_ui/_connect.dart
index 8d5028b..611834b 100644
--- a/packages/devtools_extensions/lib/src/template/_simulated_devtools_environment/connection_ui/_connect.dart
+++ b/packages/devtools_extensions/lib/src/template/_simulated_devtools_environment/connection_ui/_connect.dart

@@ -6,7 +6,6 @@
 
 class _UriConnectionDisplay extends StatelessWidget {
   const _UriConnectionDisplay({
-    required this.simController,
     required this.connected,
     required this.connectedLabel,
     required this.disconnectedLabel,
@@ -20,7 +19,6 @@
   @visibleForTesting
   static const totalControlsHeight = 45.0;
 
-  final SimulatedDevToolsController simController;
   final bool connected;
   final String connectedLabel;
   final String disconnectedLabel;
@@ -36,14 +34,12 @@
       height: totalControlsHeight,
       child: connected
           ? _ConnectedDisplay(
-              simController: simController,
               label: connectedLabel,
               onDisconnect: onDisconnect,
               currentConnection: currentConnection,
               help: help,
             )
           : _DisconnectedDisplay(
-              simController: simController,
               label: disconnectedLabel,
               hint: disconnectedHint,
               onConnect: onConnect,
@@ -55,14 +51,12 @@
 
 class _ConnectedDisplay extends StatelessWidget {
   const _ConnectedDisplay({
-    required this.simController,
     required this.label,
     required this.currentConnection,
     required this.onDisconnect,
     this.help,
   });
 
-  final SimulatedDevToolsController simController;
   final String label;
   final String Function() currentConnection;
   final VoidCallback onDisconnect;
@@ -98,14 +92,12 @@
 
 class _DisconnectedDisplay extends StatefulWidget {
   const _DisconnectedDisplay({
-    required this.simController,
     required this.label,
     required this.hint,
     required this.onConnect,
     this.help,
   });
 
-  final SimulatedDevToolsController simController;
   final String label;
   final String hint;
   final void Function(String) onConnect;

diff --git a/packages/devtools_extensions/lib/src/template/_simulated_devtools_environment/connection_ui/_dtd_connect.dart b/packages/devtools_extensions/lib/src/template/_simulated_devtools_environment/connection_ui/_dtd_connect.dart
index 439deb9..ff202af 100644
--- a/packages/devtools_extensions/lib/src/template/_simulated_devtools_environment/connection_ui/_dtd_connect.dart
+++ b/packages/devtools_extensions/lib/src/template/_simulated_devtools_environment/connection_ui/_dtd_connect.dart

@@ -13,11 +13,6 @@
     required this.onConnectionChange,
   });
 
-  @visibleForTesting
-  static const totalControlsHeight = 45.0;
-  @visibleForTesting
-  static const totalControlsWidth = 415.0;
-
   final SimulatedDevToolsController simController;
   final bool connected;
   final Future<void> Function(String?) onConnectionChange;
@@ -25,7 +20,6 @@
   @override
   Widget build(BuildContext context) {
     return _UriConnectionDisplay(
-      simController: simController,
       connected: connected,
       connectedLabel: 'Dart Tooling Daemon connection: ',
       disconnectedLabel: 'Dart Tooling Daemon Connection',

diff --git a/packages/devtools_extensions/lib/src/template/_simulated_devtools_environment/connection_ui/_vm_service_connect.dart b/packages/devtools_extensions/lib/src/template/_simulated_devtools_environment/connection_ui/_vm_service_connect.dart
index 441149f..96a834d 100644
--- a/packages/devtools_extensions/lib/src/template/_simulated_devtools_environment/connection_ui/_vm_service_connect.dart
+++ b/packages/devtools_extensions/lib/src/template/_simulated_devtools_environment/connection_ui/_vm_service_connect.dart

@@ -13,8 +13,6 @@
   });
 
   @visibleForTesting
-  static const totalControlsHeight = 45.0;
-  @visibleForTesting
   static const totalControlsWidth = 415.0;
 
   final SimulatedDevToolsController simController;
@@ -23,7 +21,6 @@
   @override
   Widget build(BuildContext context) {
     return _UriConnectionDisplay(
-      simController: simController,
       connected: connected,
       connectedLabel: 'Debugging: ',
       disconnectedLabel: 'Dart VM Service Connection',