Remove methods toJson and fromJson.

packages/devtools_app/lib/src/screens/memory/panes/leaks/controller.dart

@@ -3,7 +3,6 @@
 // found in the LICENSE file.
 
 import 'dart:async';
-import 'dart:convert';
 
 import 'package:flutter/material.dart';
 import 'package:leak_tracker/devtools_integration.dart';
@@ -116,47 +115,25 @@ class LeaksPaneController {
         notGCed: notGCedAnalyzed,
       );
 
-      _saveResultAndSetAnalysisStatus(yaml, task);
+      _saveResultAndSetAnalysisStatus(yaml);
     } catch (error) {
       analysisStatus.message.value = 'Error: $error';
       analysisStatus.status.value = AnalysisStatus.showingError;
     }
   }
 
-  void _saveResultAndSetAnalysisStatus(
-    String yaml,
-    NotGCedAnalyzerTask? task,
-  ) async {
+  void _saveResultAndSetAnalysisStatus(String yaml) {
     final now = DateTime.now();
     final yamlFile = ExportController.generateFileName(
       time: now,
       prefix: yamlFilePrefix,
       type: ExportFileType.yaml,
     );
     _exportController.downloadFile(yaml, fileName: yamlFile);
-    final String? taskFile = _saveTask(task, now);
 
-    final taskFileMessage = taskFile == null ? '' : ' and $taskFile';
-    await _setMessageWithDelay(
-      'Downloaded the leak analysis to $yamlFile$taskFileMessage.',
-    );
     analysisStatus.status.value = AnalysisStatus.showingResult;
   }
 
-  /// Saves raw analysis task for troubleshooting and deeper analysis.
-  String? _saveTask(NotGCedAnalyzerTask? task, DateTime? now) {
-    if (task == null) return null;
-
-    final json = jsonEncode(task.toJson());
-    final jsonFile = ExportController.generateFileName(
-      time: now,
-      prefix: yamlFilePrefix,
-      postfix: '.raw',
-      type: ExportFileType.json,
-    );
-    return _exportController.downloadFile(json, fileName: jsonFile);
-  }
-
   Future<void> _setMessageWithDelay(String message) async {
     analysisStatus.message.value = message;
     await delayToReleaseUiThread(micros: 5000);

packages/devtools_app/lib/src/screens/memory/panes/leaks/diagnostics/leak_analyzer.dart

@@ -10,6 +10,8 @@ import '../../../shared/heap/spanning_tree.dart';
 import 'model.dart';
 
 /// Analyzes notGCed leaks and returns result of the analysis.
+// TODO(polina-c): add tests for this method.
+// https://github.com/flutter/devtools/issues/3951
 Future<NotGCedAnalyzed> analyzeNotGCed(NotGCedAnalyzerTask task) async {
   await analyzeHeapAndSetRetainingPaths(task.heap, task.reports);
 

packages/devtools_app/lib/src/screens/memory/panes/leaks/diagnostics/model.dart

@@ -7,12 +7,6 @@ import 'package:vm_service/vm_service.dart';
 
 import '../../../../../shared/memory/adapted_heap_data.dart';
 
-/// Names for json fields.
-class _JsonFields {
-  static const String reports = 'reports';
-  static const String heap = 'heap';
-}
-
 /// Result of analysis of [notGCed] memory leaks.
 class NotGCedAnalyzed {
   NotGCedAnalyzed({
@@ -37,16 +31,6 @@ class NotGCedAnalyzerTask {
     required this.reports,
   });
 
-  factory NotGCedAnalyzerTask.fromJson(Map<String, Object?> json) =>
-      NotGCedAnalyzerTask(
-        reports: (json[_JsonFields.reports] as List<Object?>)
-            .map((e) => LeakReport.fromJson((e as Map).cast<String, Object?>()))
-            .toList(),
-        heap: AdaptedHeapData.fromJson(
-          json[_JsonFields.heap] as Map<String, Object?>,
-        ),
-      );
-
   static Future<NotGCedAnalyzerTask> fromSnapshot(
     HeapSnapshotGraph graph,
     List<LeakReport> reports,
@@ -60,9 +44,4 @@ class NotGCedAnalyzerTask {
 
   final AdaptedHeapData heap;
   final List<LeakReport> reports;
-
-  Map<String, Object?> toJson() => {
-        _JsonFields.reports: reports.map((e) => e.toJson()).toList(),
-        _JsonFields.heap: heap.toJson(),
-      };
 }

packages/devtools_app/lib/src/shared/memory/adapted_heap_data.dart

@@ -2,22 +2,15 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:collection/collection.dart';
+import 'dart:io';
+
 import 'package:flutter/foundation.dart';
 import 'package:vm_service/vm_service.dart';
 
 import '../primitives/utils.dart';
 import 'adapted_heap_object.dart';
 import 'simple_items.dart';
 
-/// Names for json fields.
-class _JsonFields {
-  static const String objects = 'objects';
-  static const String rootIndex = 'rootIndex';
-  static const String created = 'created';
-  static const String isolateId = 'isolateId';
-}
-
 @immutable
 class HeapObjectSelection {
   const HeapObjectSelection(this.heap, {required this.object});
@@ -66,21 +59,6 @@ class AdaptedHeapData {
     this.created = created ?? DateTime.now();
   }
 
-  factory AdaptedHeapData.fromJson(Map<String, dynamic> json) {
-    final createdJson = json[_JsonFields.created];
-
-    return AdaptedHeapData(
-      (json[_JsonFields.objects] as List<Object?>)
-          .mapIndexed(
-            (i, e) => AdaptedHeapObject.fromJson(e as Map<String, Object?>, i),
-          )
-          .toList(),
-      created: createdJson == null ? null : DateTime.parse(createdJson),
-      rootIndex: json[_JsonFields.rootIndex] ?? _defaultRootIndex,
-      isolateId: json[_JsonFields.isolateId] ?? '',
-    );
-  }
-
   static final _uiReleaser = UiReleaser();
 
   static Future<AdaptedHeapData> fromHeapSnapshot(
@@ -98,6 +76,18 @@ class AdaptedHeapData {
     return AdaptedHeapData(objects, isolateId: isolateId);
   }
 
+  @visibleForTesting
+  static Future<AdaptedHeapData> fromFile(
+    String fileName, {
+    String isolateId = '',
+  }) async {
+    final file = File(fileName);
+    final bytes = await file.readAsBytes();
+    final data = bytes.buffer.asByteData();
+    final graph = HeapSnapshotGraph.fromChunks([data]);
+    return AdaptedHeapData.fromHeapSnapshot(graph, isolateId: isolateId);
+  }
+
   /// Default value for rootIndex is taken from the doc:
   /// https://github.com/dart-lang/sdk/blob/main/runtime/vm/service/heap_snapshot.md#object-ids
   static const int _defaultRootIndex = 1;
@@ -126,12 +116,6 @@ class AdaptedHeapData {
     for (var i in Iterable.generate(objects.length)) objects[i].code: i,
   };
 
-  Map<String, dynamic> toJson() => {
-        _JsonFields.objects: objects.map((e) => e.toJson()).toList(),
-        _JsonFields.rootIndex: rootIndex,
-        _JsonFields.created: created.toIso8601String(),
-      };
-
   int? objectIndexByIdentityHashCode(IdentityHashCode code) =>
       _objectsByCode[code];
 

packages/devtools_app/test/memory/shared/heap/heap_analyzer_golden_test.dart

@@ -10,7 +10,7 @@ import '../../../test_infra/test_data/memory/heap/heap_data.dart';
 
 void main() {
   for (var t in goldenHeapTests) {
-    group(t.name, () {
+    group(t.fileName, () {
       late AdaptedHeapData heap;
 
       setUp(() async {
@@ -22,22 +22,22 @@ void main() {
         expect(
           heap.objects[heap.rootIndex].outRefs.length,
           greaterThan(1000),
-          reason: t.name,
+          reason: t.fileName,
         );
       });
 
       test('has exactly one object of type ${t.appClassName}.', () {
         final appObjects =
             heap.objects.where((o) => o.heapClass.className == t.appClassName);
-        expect(appObjects, hasLength(1), reason: t.name);
+        expect(appObjects, hasLength(1), reason: t.fileName);
       });
 
       test('has path to the object of type ${t.appClassName}.', () async {
         await calculateHeap(heap);
         final appObject = heap.objects
             .where((o) => o.heapClass.className == t.appClassName)
             .first;
-        expect(appObject.retainer, isNotNull, reason: t.name);
+        expect(appObject.retainer, isNotNull, reason: t.fileName);
       });
     });
   }

packages/devtools_app/test/memory/shared/heap/model_test.dart

@@ -58,27 +58,6 @@ final _heapPathTests = <_HeapPathTest>[
 ];
 
 void main() {
-  test('$AdaptedHeapData serializes.', () {
-    final json = AdaptedHeapData(
-      [
-        AdaptedHeapObject(
-          code: 1,
-          outRefs: {3, 4, 5},
-          heapClass: HeapClassName(
-            className: 'class',
-            library: 'library',
-          ),
-          shallowSize: 1,
-        ),
-      ],
-      rootIndex: 0,
-      isolateId: '',
-      created: DateTime(2000),
-    ).toJson();
-
-    expect(json, AdaptedHeapData.fromJson(json).toJson());
-  });
-
   test('$HeapPath.isRetainedBySameClass returns expected result for.', () {
     for (final t in _heapPathTests) {
       expect(

packages/devtools_app/test/test_infra/test_data/memory/heap/README.md

@@ -0,0 +1,19 @@
+To retake the snapshots:
+
+1. Create counter app with `flutter create`.
+2. Update button handler to take snapshot after increasing counter:
+
+```
+  void _incrementCounter() {
+    setState(() {
+      _counter++;
+    });
+    var fileName = 'counter_snapshot$_counter';
+    fileName = p.absolute(fileName);
+    print('saving snapshot to $fileName');
+    NativeRuntime.writeHeapSnapshotToFile(fileName);
+  }
+```
+
+3. Run the counter and click the button four times.
+4. Copy the collected files to this folder.