Use isolateManager as source of truth for isPaused.

packages/devtools_app/lib/src/screens/debugger/codeview.dart

@@ -1145,7 +1145,7 @@ class _LineItemState extends State<LineItem>
     // ignore: avoid-unused-parameters
     required bool Function() isHoverStale,
   }) async {
-    if (!serviceManager.appState.isPaused.value) return null;
+    if (!serviceManager.isMainIsolatePaused) return null;
 
     final word = wordForHover(
       event.localPosition.dx,

packages/devtools_app/lib/src/screens/debugger/controls.dart

@@ -33,24 +33,31 @@ class _DebuggingControlsState extends State<DebuggingControls>
   void didChangeDependencies() {
     super.didChangeDependencies();
     if (!initController()) return;
-    addAutoDisposeListener(serviceManager.appState.isPaused);
+    addAutoDisposeListener(
+      serviceManager.isolateManager.mainIsolateState!.isPaused,
+    );
     addAutoDisposeListener(controller.resuming);
     addAutoDisposeListener(controller.stackFramesWithLocation);
   }
 
   @override
   Widget build(BuildContext context) {
-    final isPaused = serviceManager.appState.isPaused.value;
     final resuming = controller.resuming.value;
     final hasStackFrames = controller.stackFramesWithLocation.value.isNotEmpty;
     final isSystemIsolate = controller.isSystemIsolate;
-    final canStep = isPaused && !resuming && hasStackFrames && !isSystemIsolate;
+    final canStep = serviceManager.isMainIsolatePaused &&
+        !resuming &&
+        hasStackFrames &&
+        !isSystemIsolate;
     final isVmApp = serviceManager.connectedApp?.isRunningOnDartVM ?? false;
     return SizedBox(
       height: defaultButtonHeight,
       child: Row(
         children: [
-          _pauseAndResumeButtons(isPaused: isPaused, resuming: resuming),
+          _pauseAndResumeButtons(
+            isPaused: serviceManager.isMainIsolatePaused,
+            resuming: resuming,
+          ),
           const SizedBox(width: denseSpacing),
           _stepButtons(canStep: canStep),
           const SizedBox(width: denseSpacing),

packages/devtools_app/lib/src/screens/debugger/debugger_controller.dart

@@ -79,7 +79,6 @@ class DebuggerController extends DisposableController
 
     final appState = serviceManager.appState;
 
-    appState.setPausedOnBreakpoint(false);
     _resuming.value = false;
     _lastEvent = null;
     _stackFramesWithLocation.value = [];
@@ -168,7 +167,6 @@ class DebuggerController extends DisposableController
     // and modify to detect if app is paused from the isolate
     // https://github.com/flutter/devtools/pull/4993#discussion_r1060845351
 
-    serviceManager.appState.setPausedOnBreakpoint(false);
     await _pause(false);
 
     _clearCaches();
@@ -373,7 +371,6 @@ class DebuggerController extends DisposableController
     // serviceManager.isolateManager.selectedIsolateState.isPaused.value;
     // listening for changes there instead of having separate logic.
     await _getStackOperation?.cancel();
-    serviceManager.appState.setPausedOnBreakpoint(paused);
 
     _log.log('_pause(running: ${!paused})');
 

packages/devtools_app/lib/src/screens/debugger/debugger_screen.dart

@@ -360,27 +360,29 @@ class DebuggerStatus extends StatefulWidget {
 class _DebuggerStatusState extends State<DebuggerStatus> with AutoDisposeMixin {
   String _status = '';
 
+  bool get _isPaused => serviceManager.isMainIsolatePaused;
+
   @override
   void initState() {
     super.initState();
 
-    addAutoDisposeListener(
-      serviceManager.appState.isPaused,
-      () => unawaited(
-        _updateStatus(),
-      ),
-    );
-
+    _updateStatusOnPause();
     unawaited(_updateStatus());
   }
 
   @override
   void didUpdateWidget(DebuggerStatus oldWidget) {
     super.didUpdateWidget(oldWidget);
 
-    // todo: should we check that widget.controller != oldWidget.controller?
+    if (widget.controller == oldWidget.controller) return;
+
+    cancelListeners();
+    _updateStatusOnPause();
+  }
+
+  void _updateStatusOnPause() {
     addAutoDisposeListener(
-      serviceManager.appState.isPaused,
+      serviceManager.isolateManager.mainIsolateState!.isPaused,
       () => unawaited(
         _updateStatus(),
       ),
@@ -406,9 +408,7 @@ class _DebuggerStatusState extends State<DebuggerStatus> with AutoDisposeMixin {
   }
 
   Future<String> _computeStatus() async {
-    final paused = serviceManager.appState.isPaused.value;
-
-    if (!paused) {
+    if (!_isPaused) {
       return 'running';
     }
 
@@ -447,20 +447,21 @@ class _FloatingDebuggerControlsState extends State<FloatingDebuggerControls>
     with
         AutoDisposeMixin,
         ProvidedControllerMixin<DebuggerController, FloatingDebuggerControls> {
-  late bool paused;
-
   late double controlHeight;
 
+  bool get _isPaused => serviceManager.isMainIsolatePaused;
+
   @override
   void didChangeDependencies() {
     super.didChangeDependencies();
     if (!initController()) return;
-    paused = serviceManager.appState.isPaused.value;
-    controlHeight = paused ? defaultButtonHeight : 0.0;
-    addAutoDisposeListener(serviceManager.appState.isPaused, () {
+    cancelListeners();
+
+    controlHeight = _isPaused ? defaultButtonHeight : 0.0;
+    addAutoDisposeListener(
+        serviceManager.isolateManager.mainIsolateState!.isPaused, () {
       setState(() {
-        paused = serviceManager.appState.isPaused.value;
-        if (paused) {
+        if (_isPaused) {
           controlHeight = defaultButtonHeight;
         }
       });
@@ -470,10 +471,10 @@ class _FloatingDebuggerControlsState extends State<FloatingDebuggerControls>
   @override
   Widget build(BuildContext context) {
     return AnimatedOpacity(
-      opacity: paused ? 1.0 : 0.0,
+      opacity: _isPaused ? 1.0 : 0.0,
       duration: longDuration,
       onEnd: () {
-        if (!paused) {
+        if (!_isPaused) {
           setState(() {
             controlHeight = 0.0;
           });

packages/devtools_app/lib/src/screens/debugger/program_explorer_controller.dart

@@ -48,8 +48,6 @@ class ProgramExplorerController extends DisposableController
   ValueListenable<int> get selectedNodeIndex => _selectedNodeIndex;
   final _selectedNodeIndex = ValueNotifier<int>(0);
 
-  IsolateRef? _isolate;
-
   /// Notifies that the controller has finished initializing.
   ValueListenable<bool> get initialized => _initialized;
   final _initialized = ValueNotifier<bool>(false);
@@ -76,10 +74,10 @@ class ProgramExplorerController extends DisposableController
     }
     _initializing = true;
 
-    _isolate = serviceManager.isolateManager.selectedIsolate.value;
-    final libraries = _isolate != null
+    final isolate = serviceManager.isolateManager.selectedIsolate.value;
+    final libraries = isolate != null
         ? serviceManager.isolateManager
-            .isolateDebuggerState(_isolate)!
+            .isolateState(isolate)
             .isolateNow!
             .libraries!
         : <LibraryRef>[];

packages/devtools_app/lib/src/screens/debugger/program_explorer_model.dart

@@ -86,7 +86,7 @@ class VMServiceObjectNode extends TreeNode<VMServiceObjectNode> {
         final service = serviceManager.service!;
         final isolate = serviceManager.isolateManager.selectedIsolate.value!;
         final libRef = serviceManager.isolateManager
-            .isolateDebuggerState(isolate)!
+            .isolateState(isolate)
             .isolateNow!
             .libraries!
             .firstWhere(
@@ -194,7 +194,7 @@ class VMServiceObjectNode extends TreeNode<VMServiceObjectNode> {
     // part of a package. Otherwise, it's a file path and its directory should
     // appear near the top of the list anyway.
     final rootLibUri = serviceManager
-        .isolateManager.mainIsolateDebuggerState?.isolateNow?.rootLib?.uri;
+        .isolateManager.mainIsolateState?.isolateNow?.rootLib?.uri;
     if (rootLibUri != null) {
       if (rootLibUri.startsWith('package:') ||
           rootLibUri.startsWith('google3:')) {

packages/devtools_app/lib/src/screens/inspector/inspector_tree_controller.dart

@@ -775,7 +775,7 @@ class _InspectorTreeState extends State<InspectorTree>
     autoDisposeFocusNode(_focusNode);
 
     callOnceWhenReady(
-      trigger: serviceManager.isolateManager.mainIsolateDebuggerState!.isPaused,
+      trigger: serviceManager.isolateManager.mainIsolateState!.isPaused,
       callback: _bindToController,
       readyWhen: (triggerValue) => triggerValue == false,
     );

packages/devtools_app/lib/src/service/isolate_manager.dart

@@ -60,16 +60,12 @@ class IsolateManager extends Disposer {
     await _initIsolates(isolates);
   }
 
-  IsolateState? get mainIsolateDebuggerState {
+  IsolateState? get mainIsolateState {
     return _mainIsolate.value != null
         ? _isolateStates[_mainIsolate.value!]
         : null;
   }
 
-  IsolateState? isolateDebuggerState(IsolateRef? isolate) {
-    return isolate != null ? _isolateStates[isolate] : null;
-  }
-
   /// Return a unique, monotonically increasing number for this Isolate.
   int? isolateIndex(IsolateRef isolateRef) {
     if (!_isolateIndexMap.containsKey(isolateRef.id)) {

packages/devtools_app/lib/src/service/service_manager.dart

@@ -78,6 +78,12 @@ class ServiceConnectionManager {
 
   final isolateManager = IsolateManager();
 
+  /// Proxy to state inside the isolateManager, for code consizeness.
+  ///
+  /// Defaults to false if there is no main isolate.
+  bool get isMainIsolatePaused =>
+      isolateManager.mainIsolateState?.isPaused.value ?? false;
+
   final consoleService = ConsoleService();
 
   final resolvedUriManager = ResolvedUriManager();
@@ -547,7 +553,7 @@ class ServiceConnectionManager {
     if (uri == null) return false;
     assert(_serviceAvailable.isCompleted);
     assert(serviceManager.isolateManager.mainIsolate.value != null);
-    final isolate = isolateManager.mainIsolateDebuggerState!.isolateNow;
+    final isolate = isolateManager.mainIsolateState!.isolateNow;
     return (isolate?.libraries ?? [])
         .map((ref) => ref.uri)
         .toList()

packages/devtools_app/lib/src/shared/connected_app.dart

@@ -250,12 +250,6 @@ class AppState extends DisposableController with AutoDisposeControllerMixin {
   final _variables = ValueNotifier<List<DartObjectNode>>([]);
   void setVariables(List<DartObjectNode> value) => _variables.value = value;
 
-  ValueListenable<bool> get isPaused => _isPaused;
-  final _isPaused = ValueNotifier<bool>(false);
-
-  /// This setter should be invoked only by debugger.
-  void setPausedOnBreakpoint(bool value) => _isPaused.value = value;
-
   ValueListenable<Frame?> get currentFrame => _currentFrame;
   final _currentFrame = ValueNotifier<Frame?>(null);
   void setCurrentFrame(Frame? value) => _currentFrame.value = value;
@@ -267,7 +261,6 @@ class AppState extends DisposableController with AutoDisposeControllerMixin {
   @override
   void dispose() {
     _variables.dispose();
-    _isPaused.dispose();
     _currentFrame.dispose();
     super.dispose();
   }

packages/devtools_app/lib/src/shared/console/eval/eval_service.dart

@@ -68,7 +68,7 @@ class EvalService extends DisposableController with AutoDisposeControllerMixin {
   Future<Response> evalAtCurrentFrame(String expression) {
     final appState = serviceManager.appState;
 
-    if (!appState.isPaused.value) {
+    if (!serviceManager.isMainIsolatePaused) {
       return Future.error(
         RPCError.withDetails(
           'evaluateInFrame',

packages/devtools_app/lib/src/shared/console/widgets/evaluate.dart

@@ -300,8 +300,7 @@ class ExpressionEvalFieldState extends State<ExpressionEvalField>
     if (expressionText.isEmpty) return;
 
     // Only try to eval if we are paused.
-    if (!serviceManager
-        .isolateManager.mainIsolateDebuggerState!.isPaused.value) {
+    if (!serviceManager.isMainIsolatePaused) {
       notificationService
           .push('Application must be paused to support expression evaluation.');
       return;

packages/devtools_app/lib/src/shared/inspector_service.dart

@@ -97,11 +97,7 @@ abstract class InspectorServiceBase extends DisposableController
   /// The VM Service protocol must be used when paused at a breakpoint as the
   /// Daemon API calls won't execute until after the current frame is done
   /// rendering.
-  bool get useDaemonApi {
-    return !(serviceManager
-            .isolateManager.mainIsolateDebuggerState?.isPaused.value ??
-        false);
-  }
+  bool get useDaemonApi => !serviceManager.isMainIsolatePaused;
 
   @override
   void dispose() {

packages/devtools_app/lib/src/shared/preferences.dart

@@ -154,8 +154,7 @@ class InspectorPreferencesController extends DisposableController
       () {
         if (_mainScriptDir != null &&
             serviceManager.isolateManager.mainIsolate.value != null) {
-          final debuggerState =
-              serviceManager.isolateManager.mainIsolateDebuggerState;
+          final debuggerState = serviceManager.isolateManager.mainIsolateState;
 
           if (debuggerState?.isPaused.value == false) {
             // the isolate is already unpaused, we can try to load

packages/devtools_app/test/debugger/debugger_floating_test.dart

@@ -27,7 +27,9 @@ void main() {
   setGlobal(NotificationService, NotificationService());
   fakeServiceManager.consoleService.ensureServiceInitialized();
 
-  fakeServiceManager.appState.setPausedOnBreakpoint(true);
+  setUp(() {
+    fakeServiceManager.isMainIsolatePaused = true;
+  });
 
   Future<void> pumpControls(WidgetTester tester) async {
     await tester.pumpWidget(
@@ -41,6 +43,7 @@ void main() {
 
   testWidgets('display as expected', (WidgetTester tester) async {
     await pumpControls(tester);
+
     final animatedOpacityFinder = find.byType(AnimatedOpacity);
     expect(animatedOpacityFinder, findsOneWidget);
     final animatedOpacity =
@@ -85,7 +88,9 @@ void main() {
   });
 
   testWidgets('are hidden when app is not paused', (WidgetTester tester) async {
-    fakeServiceManager.appState.setPausedOnBreakpoint(false);
+    final state =
+        fakeServiceManager.isolateManager.mainIsolateState! as MockIsolateState;
+    state.isPaused.value = false;
     await pumpControls(tester);
     final animatedOpacityFinder = find.byType(AnimatedOpacity);
     expect(animatedOpacityFinder, findsOneWidget);

packages/devtools_app/test/debugger/debugger_screen_paused_test.dart

@@ -80,7 +80,9 @@ void main() {
   }
 
   setUp(() {
-    fakeServiceManager.appState.setPausedOnBreakpoint(true);
+    final state =
+        fakeServiceManager.isolateManager.mainIsolateState! as MockIsolateState;
+    state.isPaused.value = true;
   });
 
   testWidgetsWithWindowSize(

packages/devtools_app/test/shared/scaffold_debugger_test.dart

@@ -27,6 +27,7 @@ void main() {
   when(mockServiceManager.errorBadgeManager).thenReturn(mockErrorBadgeManager);
   when(mockErrorBadgeManager.errorCountNotifier(any))
       .thenReturn(ValueNotifier<int>(0));
+  when(mockServiceManager.isMainIsolatePaused).thenReturn(false);
 
   setGlobal(ServiceConnectionManager, mockServiceManager);
   setGlobal(FrameworkController, FrameworkController());

packages/devtools_app/test/shared/scaffold_debugging_controls_test.dart

@@ -55,7 +55,10 @@ void main() {
         AppState(mockServiceManager.isolateManager.selectedIsolate),
       );
       final mockDebuggerController = MockDebuggerController();
-      mockServiceManager.appState.setPausedOnBreakpoint(true);
+      final state =
+          serviceManager.isolateManager.mainIsolateState! as MockIsolateState;
+      state.isPaused.value = true;
+      when(mockServiceManager.isMainIsolatePaused).thenReturn(false);
 
       await tester.pumpWidget(
         wrapWithControllers(

packages/devtools_app/test/shared/scaffold_profile_test.dart

@@ -52,7 +52,9 @@ void main() {
       when(mockServiceManager.connectedApp).thenReturn(mockConnectedApp);
       final mockDebuggerController = MockDebuggerController();
 
-      mockServiceManager.appState.setPausedOnBreakpoint(true);
+      final state =
+          serviceManager.isolateManager.mainIsolateState! as MockIsolateState;
+      state.isPaused.value = true;
 
       await tester.pumpWidget(
         wrapWithControllers(

packages/devtools_app/test/shared/service_extension_widgets_test.dart

@@ -28,6 +28,7 @@ Future<void> main() async {
       .thenReturn(AppState(mockServiceManager.isolateManager.selectedIsolate));
   when(mockServiceManager.runDeviceBusyTask(Future<void>.value()))
       .thenAnswer((_) => Future<void>.value());
+  when(mockServiceManager.isMainIsolatePaused).thenReturn(false);
   setGlobal(ServiceConnectionManager, mockServiceManager);
   setGlobal(NotificationService, NotificationService());