diff --git a/dwds/lib/dwds.dart b/dwds/lib/dwds.dart
index f76b640a6..ca9459921 100644
--- a/dwds/lib/dwds.dart
+++ b/dwds/lib/dwds.dart
@@ -58,6 +58,7 @@ class Dwds {
     LogWriter logWriter,
     bool verbose,
     bool enableDebugExtension,
+    WipDebugger wipDebugger,
   }) async {
     hostname ??= 'localhost';
     reloadConfiguration ??= ReloadConfiguration.none;
@@ -99,6 +100,7 @@ class Dwds {
       hostname,
       verbose,
       logWriter,
+      wipDebugger,
     );
     cascade = cascade.add(devHandler.handler).add(assetHandler.handler);
 
diff --git a/dwds/lib/src/debugging/inspector.dart b/dwds/lib/src/debugging/inspector.dart
index fb53579ec..351cb2f97 100644
--- a/dwds/lib/src/debugging/inspector.dart
+++ b/dwds/lib/src/debugging/inspector.dart
@@ -38,7 +38,7 @@ class AppInspector extends Domain {
   /// Map of [ScriptRef] id to containing [LibraryRef] id.
   final _scriptIdToLibraryId = <String, String>{};
 
-  final WipConnection _tabConnection;
+  final WipDebugger _wipDebugger;
   final AssetHandler _assetHandler;
   final Debugger _debugger;
   final Isolate isolate;
@@ -49,10 +49,10 @@ class AppInspector extends Domain {
 
   AppInspector._(
     this.isolate,
-    this._tabConnection,
     this._assetHandler,
     this._debugger,
     this._root,
+    this._wipDebugger,
   )   : isolateRef = _toIsolateRef(isolate),
         super.forInspector();
 
@@ -81,7 +81,7 @@ class AppInspector extends Domain {
     ..number = isolate.number;
 
   static Future<AppInspector> initialize(
-    WipConnection tabConnection,
+    WipDebugger wipDebugger,
     AssetHandler assetHandler,
     Debugger debugger,
     String root,
@@ -96,7 +96,7 @@ class AppInspector extends Domain {
       ..libraries = []
       ..extensionRPCs = [];
     var inspector =
-        AppInspector._(isolate, tabConnection, assetHandler, debugger, root);
+        AppInspector._(isolate, assetHandler, debugger, root, wipDebugger);
     await inspector._initialize();
     return inspector;
   }
@@ -123,7 +123,7 @@ class AppInspector extends Domain {
   return library.$expression;
 })();
     ''';
-      result = await _tabConnection.runtime.sendCommand('Runtime.evaluate',
+      result = await _wipDebugger.sendCommand('Runtime.evaluate',
           params: {'expression': evalExpression});
       handleErrorIfPresent(result,
           evalContents: evalExpression,
@@ -139,8 +139,8 @@ function($argsString) {
   return library.$expression;
 }
     ''';
-      result = await _tabConnection.runtime
-          .sendCommand('Runtime.callFunctionOn', params: {
+      result =
+          await _wipDebugger.sendCommand('Runtime.callFunctionOn', params: {
         'functionDeclaration': evalExpression,
         'arguments': arguments,
         // TODO(jakemac): Use the executionContext instead, or possibly the
@@ -265,7 +265,7 @@ function($argsString) {
       return result;
     })()
     ''';
-    var result = await _tabConnection.runtime.sendCommand('Runtime.evaluate',
+    var result = await _wipDebugger.sendCommand('Runtime.evaluate',
         params: {'expression': expression, 'returnByValue': true});
     handleErrorIfPresent(result, evalContents: expression);
     var classDescriptors = (result.result['result']['value']['classes'] as List)
@@ -405,8 +405,7 @@ function($argsString) {
   Future<List<LibraryRef>> _getLibraryRefs() async {
     if (_libraryRefs.isNotEmpty) return _libraryRefs.values.toList();
     var expression = "require('dart_sdk').dart.getLibraries();";
-    var librariesResult = await _tabConnection.runtime.sendCommand(
-        'Runtime.evaluate',
+    var librariesResult = await _wipDebugger.sendCommand('Runtime.evaluate',
         params: {'expression': expression, 'returnByValue': true});
     handleErrorIfPresent(librariesResult, evalContents: expression);
     var libraries =
@@ -424,8 +423,7 @@ function($argsString) {
   /// Runs an eval on the page to compute all existing registered extensions.
   Future<List<String>> _getExtensionRpcs() async {
     var expression = "require('dart_sdk').developer._extensions.keys.toList();";
-    var extensionsResult = await _tabConnection.runtime.sendCommand(
-        'Runtime.evaluate',
+    var extensionsResult = await _wipDebugger.sendCommand('Runtime.evaluate',
         params: {'expression': expression, 'returnByValue': true});
     handleErrorIfPresent(extensionsResult, evalContents: expression);
     return List.from(extensionsResult.result['result']['value'] as List);
diff --git a/dwds/lib/src/handlers/dev_handler.dart b/dwds/lib/src/handlers/dev_handler.dart
index f15ecf361..94f55b60d 100644
--- a/dwds/lib/src/handlers/dev_handler.dart
+++ b/dwds/lib/src/handlers/dev_handler.dart
@@ -39,6 +39,7 @@ class DevHandler {
   final bool _verbose;
   final void Function(Level, String) _logWriter;
   final Future<ChromeConnection> Function() _chromeConnection;
+  final WipDebugger _wipDebugger;
 
   Stream<AppConnection> get connectedApps => _connectedApps.stream;
 
@@ -50,6 +51,7 @@ class DevHandler {
     this._hostname,
     this._verbose,
     this._logWriter,
+    this._wipDebugger,
   ) {
     _sub = buildResults.listen(_emitBuildResults);
     _listen();
@@ -87,6 +89,7 @@ class DevHandler {
       chromeConnection,
       _assetHandler.getRelativeAsset,
       appInstanceId,
+      _wipDebugger,
       onResponse: _verbose
           ? (response) {
               if (response['error'] == null) return;
diff --git a/dwds/lib/src/services/chrome_proxy_service.dart b/dwds/lib/src/services/chrome_proxy_service.dart
index 269fe260c..36cd3e542 100644
--- a/dwds/lib/src/services/chrome_proxy_service.dart
+++ b/dwds/lib/src/services/chrome_proxy_service.dart
@@ -46,6 +46,8 @@ class ChromeProxyService implements VmServiceInterface {
   // TODO(grouma) - This should be class private.
   final WipConnection tabConnection;
 
+  final WipDebugger _wipDebugger;
+
   final AssetHandler _assetHandler;
 
   /// Provides debugger-related functionality.
@@ -61,10 +63,14 @@ class ChromeProxyService implements VmServiceInterface {
     this._tab,
     this.tabConnection,
     this._assetHandler,
+    this._wipDebugger,
   );
 
-  static Future<ChromeProxyService> create(ChromeConnection chromeConnection,
-      AssetHandler assetHandler, String appInstanceId) async {
+  static Future<ChromeProxyService> create(
+      ChromeConnection chromeConnection,
+      AssetHandler assetHandler,
+      String appInstanceId,
+      WipDebugger wipDebugger) async {
     ChromeTab appTab;
     for (var tab in await chromeConnection.getTabs()) {
       if (tab.url.startsWith('chrome-extensions:')) continue;
@@ -84,13 +90,16 @@ class ChromeProxyService implements VmServiceInterface {
     var tabConnection = await appTab.connect();
     await tabConnection.runtime.enable();
 
+    wipDebugger = WipDebugger(tabConnection);
+
     // TODO: What about `architectureBits`, `targetCPU`, `hostCPU` and `pid`?
     final vm = VM()
       ..isolates = []
       ..name = 'ChromeDebugProxy'
       ..startTime = DateTime.now().millisecondsSinceEpoch
       ..version = Platform.version;
-    var service = ChromeProxyService._(vm, appTab, tabConnection, assetHandler);
+    var service = ChromeProxyService._(
+        vm, appTab, tabConnection, assetHandler, wipDebugger);
     await service._initialize();
     await service.createIsolate();
     return service;
@@ -121,7 +130,7 @@ class ChromeProxyService implements VmServiceInterface {
     }
 
     _inspector = await AppInspector.initialize(
-      tabConnection,
+      _wipDebugger,
       _assetHandler,
       _debugger,
       uri,
@@ -206,8 +215,7 @@ class ChromeProxyService implements VmServiceInterface {
 require("dart_sdk").developer.invokeExtension(
     "$method", JSON.stringify(${jsonEncode(stringArgs)}));
 ''';
-    var response =
-        await tabConnection.runtime.sendCommand('Runtime.evaluate', params: {
+    var response = await _wipDebugger.sendCommand('Runtime.evaluate', params: {
       'expression': expression,
       'awaitPromise': true,
     });
diff --git a/dwds/lib/src/services/debug_service.dart b/dwds/lib/src/services/debug_service.dart
index 440eae83f..2d02b64f9 100644
--- a/dwds/lib/src/services/debug_service.dart
+++ b/dwds/lib/src/services/debug_service.dart
@@ -75,12 +75,13 @@ class DebugService {
     String hostname,
     ChromeConnection chromeConnection,
     Future<String> Function(String) assetHandler,
-    String appInstanceId, {
+    String appInstanceId,
+    WipDebugger wipDebugger, {
     void Function(Map<String, dynamic>) onRequest,
     void Function(Map<String, dynamic>) onResponse,
   }) async {
     var chromeProxyService = await ChromeProxyService.create(
-        chromeConnection, assetHandler, appInstanceId);
+        chromeConnection, assetHandler, appInstanceId, wipDebugger);
     var serviceExtensionRegistry = ServiceExtensionRegistry();
     var authToken = _makeAuthToken();
     var innerHandler = webSocketHandler(_createNewConnectionHandler(
diff --git a/dwds/test/fixtures/context.dart b/dwds/test/fixtures/context.dart
index 65f405958..07b103f4e 100644
--- a/dwds/test/fixtures/context.dart
+++ b/dwds/test/fixtures/context.dart
@@ -9,6 +9,7 @@ import 'package:build_daemon/client.dart';
 import 'package:build_daemon/data/build_status.dart';
 import 'package:build_daemon/data/build_target.dart';
 import 'package:dwds/dwds.dart';
+import 'package:dwds/src/servers/extension_backend.dart';
 import 'package:dwds/src/services/chrome_proxy_service.dart';
 import 'package:dwds/src/utilities/shared.dart';
 import 'package:http/http.dart' as http;
@@ -30,6 +31,8 @@ class TestContext {
   AppConnection appConnection;
   DebugConnection debugConnection;
   ChromeProxyService chromeProxyService;
+  ExtensionBackend extensionBackend;
+  WipDebugger wipDebugger;
   int port;
   File _entryFile;
   String _entryContents;
@@ -99,6 +102,7 @@ class TestContext {
       () async => connection,
       reloadConfiguration,
       serveDevTools,
+      wipDebugger,
     );
 
     appUrl = 'http://localhost:$port/$path';
@@ -115,8 +119,8 @@ class TestContext {
       var result = await http.get('http://localhost:$port/$path');
       return result.body;
     };
-    chromeProxyService = await ChromeProxyService.create(
-        connection, assetHandler, appConnection.request.instanceId);
+    chromeProxyService = await ChromeProxyService.create(connection,
+        assetHandler, appConnection.request.instanceId, wipDebugger);
   }
 
   Future<Null> tearDown() async {
diff --git a/dwds/test/fixtures/server.dart b/dwds/test/fixtures/server.dart
index c793d44a0..8cceb691e 100644
--- a/dwds/test/fixtures/server.dart
+++ b/dwds/test/fixtures/server.dart
@@ -48,6 +48,7 @@ class TestServer {
     Future<ChromeConnection> Function() chromeConnection,
     ReloadConfiguration reloadConfiguration,
     bool serveDevTools,
+    WipDebugger wipDebugger,
   ) async {
     var pipeline = const Pipeline();
 
@@ -64,6 +65,7 @@ class TestServer {
       reloadConfiguration: reloadConfiguration,
       serveDevTools: serveDevTools,
       verbose: true,
+      wipDebugger: wipDebugger,
     );
 
     var server = await HttpMultiServer.bind('localhost', port);