add widgetLocationIdMap extension.

packages/flutter/lib/src/widgets/service_extensions.dart

@@ -135,7 +135,22 @@ enum WidgetInspectorServiceExtensions {
   ///   extension is registered.
   trackRebuildDirtyWidgets,
 
+  /// Name of service extension that, when called, returns the mapping of
+  /// widget locations to ids.
+  ///
+  /// This service extension is only supported if
+  /// [WidgetInspectorService._widgetCreationTracked] is true.
+  ///
+  /// See also:
+  ///
+  /// * [trackRebuildDirtyWidgets], which toggles dispatching events that use
+  ///   these ids to efficiently indicate the locations of widgets.
+  /// * [WidgetInspectorService.initServiceExtensions], where the service
+  ///   extension is registered.
+  widgetLocationIdMap,
+
   /// Name of service extension that, when called, determines whether
+  /// [WidgetInspectorService._trackRepaintWidgets], which determines whether
   /// a callback is invoked for every [RenderObject] painted each frame.
   ///
   /// See also:

packages/flutter/lib/src/widgets/widget_inspector.dart

@@ -1050,6 +1050,13 @@ mixin WidgetInspectorService {
         },
       );
 
+      _registerSignalServiceExtension(
+        name: WidgetInspectorServiceExtensions.widgetLocationIdMap.name,
+        callback: () {
+          return _locationIdMapToJson();
+        },
+       );
+
       _registerBoolServiceExtension(
         name: WidgetInspectorServiceExtensions.trackRepaintWidgets.name,
         getter: () async => _trackRepaintWidgets,
@@ -2259,9 +2266,11 @@ mixin WidgetInspectorService {
   bool? _widgetCreationTracked;
 
   late Duration _frameStart;
+  late int _frameNumber;
 
   void _onFrameStart(Duration timeStamp) {
     _frameStart = timeStamp;
+    _frameNumber = PlatformDispatcher.instance.frameData.frameNumber;
     SchedulerBinding.instance.addPostFrameCallback(_onFrameEnd);
   }
 
@@ -2275,7 +2284,13 @@ mixin WidgetInspectorService {
   }
 
   void _postStatsEvent(String eventName, _ElementLocationStatsTracker stats) {
-    postEvent(eventName, stats.exportToJson(_frameStart));
+    postEvent(
+      eventName,
+      stats.exportToJson(
+        _frameStart,
+        frameNumber: _frameNumber,
+      ),
+    );
   }
 
   /// All events dispatched by a [WidgetInspectorService] use this method
@@ -2466,7 +2481,7 @@ class _ElementLocationStatsTracker {
 
   /// Exports the current counts and then resets the stats to prepare to track
   /// the next frame of data.
-  Map<String, dynamic> exportToJson(Duration startTime) {
+  Map<String, dynamic> exportToJson(Duration startTime, {required int frameNumber}) {
     final List<int> events = List<int>.filled(active.length * 2, 0);
     int j = 0;
     for (final _LocationCount stat in active) {
@@ -2476,6 +2491,7 @@ class _ElementLocationStatsTracker {
 
     final Map<String, dynamic> json = <String, dynamic>{
       'startTime': startTime.inMicroseconds,
+      'frameNumber': frameNumber,
       'events': events,
     };
 
@@ -3120,11 +3136,21 @@ class _InspectorOverlayLayer extends Layer {
     final Rect targetRect = MatrixUtils.transformRect(
       state.selected.transform, state.selected.rect,
     );
-    final Offset target = Offset(targetRect.left, targetRect.center.dy);
-    const double offsetFromWidget = 9.0;
-    final double verticalOffset = (targetRect.height) / 2 + offsetFromWidget;
-
-    _paintDescription(canvas, state.tooltip, state.textDirection, target, verticalOffset, size, targetRect);
+    if (!targetRect.hasNaN) {
+      final Offset target = Offset(targetRect.left, targetRect.center.dy);
+      const double offsetFromWidget = 9.0;
+      final double verticalOffset = (targetRect.height) / 2 + offsetFromWidget;
+
+      _paintDescription(
+        canvas,
+        state.tooltip,
+        state.textDirection,
+        target,
+        verticalOffset,
+        size,
+        targetRect,
+     );
+    }
 
     // TODO(jacobr): provide an option to perform a debug paint of just the
     // selected widget.
@@ -3518,6 +3544,27 @@ int _toLocationId(_Location location) {
   return id;
 }
 
+Map<String, dynamic> _locationIdMapToJson() {
+  final Map<String, Map<String, List<Object?>>> fileLocationsMap = <String, Map<String, List<Object?>>>{};
+  for (final MapEntry<_Location, int> entry in _locationToId.entries) {
+    final _Location location = entry.key;
+    final Map<String, List<Object?>> locations = fileLocationsMap.putIfAbsent(
+      location.file, () => <String, List<Object?>>{
+        'ids': <int>[],
+        'lines': <int>[],
+        'columns': <int>[],
+        'names': <String?>[],
+      },
+    );
+
+    locations['ids']!.add(entry.value);
+    locations['lines']!.add(location.line);
+    locations['columns']!.add(location.column);
+    locations['names']!.add(location.name);
+  }
+  return fileLocationsMap;
+}
+
 /// A delegate that configures how a hierarchy of [DiagnosticsNode]s are
 /// serialized by the Flutter Inspector.
 @visibleForTesting