Create tab 'Leaks'

packages/devtools_app/lib/src/screens/memory/memory_controller.dart

@@ -298,6 +298,9 @@ class MemoryController extends DisposableController
   ValueListenable<DateTime?> get selectedSnapshotNotifier =>
       _selectedSnapshotNotifier;
 
+  final _shouldShowLeaksTab = ValueNotifier<bool>(false);
+  ValueListenable<bool> get shouldShowLeaksTab => _shouldShowLeaksTab;
+
   static String formattedTimestamp(DateTime? timestamp) =>
       timestamp != null ? DateFormat('MMM dd HH:mm:ss').format(timestamp) : '';
 
@@ -815,7 +818,15 @@ class MemoryController extends DisposableController
     // TODO(terry): Need an event on the controller for this too?
   }
 
-  void _handleConnectionStart(ServiceConnectionManager serviceManager) {
+  void _refreshShouldShowLeaksTab() {
+    _shouldShowLeaksTab.value = serviceManager.serviceExtensionManager
+        .hasServiceExtension(memoryLeakTrackingExtensionName)
+        .value;
+  }
+
+  void _handleConnectionStart(ServiceConnectionManager serviceManager) async {
+    _refreshShouldShowLeaksTab();
+
     _memoryTracker = MemoryTracker(this);
     _memoryTracker!.start();
 

packages/devtools_app/lib/src/screens/memory/memory_heap_tree_view.dart

@@ -32,6 +32,7 @@ import 'memory_graph_model.dart';
 import 'memory_heap_treemap.dart';
 import 'memory_instance_tree_view.dart';
 import 'memory_snapshot_models.dart';
+import 'panes/leaks/leaks_pane.dart';
 
 const memorySearchFieldKeyName = 'MemorySearchFieldKey';
 
@@ -143,26 +144,16 @@ class HeapTreeViewState extends State<HeapTree>
   static const dartHeapAnalysisTabKey = Key('Dart Heap Analysis Tab');
   @visibleForTesting
   static const dartHeapAllocationsTabKey = Key('Dart Heap Allocations Tab');
+  @visibleForTesting
+  static const leaksTabKey = Key('Leaks Tab');
 
   /// Below constants should match index for Tab index in DartHeapTabs.
   static const int analysisTabIndex = 0;
   static const int allocationsTabIndex = 1;
 
   static const _gaPrefix = 'memoryTab';
 
-  static final List<Tab> dartHeapTabs = [
-    DevToolsTab.create(
-      key: dartHeapAnalysisTabKey,
-      gaPrefix: _gaPrefix,
-      tabName: 'Analysis',
-    ),
-    DevToolsTab.create(
-      key: dartHeapAllocationsTabKey,
-      gaPrefix: _gaPrefix,
-      tabName: 'Allocations',
-    ),
-  ];
-
+  late List<Tab> _tabs;
   late TabController _tabController;
 
   Widget? snapshotDisplay;
@@ -192,19 +183,47 @@ class HeapTreeViewState extends State<HeapTree>
   void initState() {
     super.initState();
 
-    _tabController = TabController(length: dartHeapTabs.length, vsync: this);
-    addAutoDisposeListener(_tabController);
-
     _animation = _setupBubbleAnimationController();
   }
 
+  void _initTabs() {
+    _tabs = [
+      DevToolsTab.create(
+        key: dartHeapAnalysisTabKey,
+        gaPrefix: _gaPrefix,
+        tabName: 'Analysis',
+      ),
+      DevToolsTab.create(
+        key: dartHeapAllocationsTabKey,
+        gaPrefix: _gaPrefix,
+        tabName: 'Allocations',
+      ),
+      if (widget.controller.shouldShowLeaksTab.value)
+        DevToolsTab.create(
+          key: leaksTabKey,
+          gaPrefix: _gaPrefix,
+          tabName: 'Leaks',
+        ),
+    ];
+
+    _tabController = TabController(length: _tabs.length, vsync: this);
+  }
+
   @override
   void didChangeDependencies() {
     super.didChangeDependencies();
     if (!initController()) return;
 
     cancelListeners();
 
+    _initTabs();
+
+    addAutoDisposeListener(controller.shouldShowLeaksTab, () {
+      setState(() {
+        _initTabs();
+      });
+    });
+
     addAutoDisposeListener(controller.selectedSnapshotNotifier, () {
       setState(() {
         controller.computeAllLibraries(rebuild: true);
@@ -418,7 +437,7 @@ class HeapTreeViewState extends State<HeapTree>
                 labelColor: themeData.textTheme.bodyText1!.color,
                 isScrollable: true,
                 controller: _tabController,
-                tabs: HeapTreeViewState.dartHeapTabs,
+                tabs: _tabs,
               ),
               _buildSearchFilterControls(),
             ],
@@ -454,6 +473,10 @@ class HeapTreeViewState extends State<HeapTree>
                     ],
                   ),
                 ),
+
+                // Leaks tab.
+                if (controller.shouldShowLeaksTab.value)
+                  const KeepAliveWrapper(child: LeaksPane()),
               ],
             ),
           ),

packages/devtools_app/lib/src/screens/memory/panes/leaks/LEAK_TRACKING.md

@@ -0,0 +1,3 @@
+# Memory Leaks Tracking with DevTools
+
+This page and functionality are under construction. See https://github.com/flutter/devtools/issues/3951.

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

@@ -0,0 +1,20 @@
+import 'package:flutter/material.dart';
+
+class LeaksPane extends StatefulWidget {
+  const LeaksPane({Key? key}) : super(key: key);
+
+  @override
+  State<LeaksPane> createState() => _LeaksPaneState();
+}
+
+class _LeaksPaneState extends State<LeaksPane> {
+  @override
+  Widget build(BuildContext context) {
+    return Column(
+      crossAxisAlignment: CrossAxisAlignment.start,
+      children: const [
+        Text('Memory leak tracking functionality will be here.'),
+      ],
+    );
+  }
+}

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

@@ -4,6 +4,7 @@
 
 library service_extensions;
 
+import 'package:devtools_shared/devtools_shared.dart';
 import 'package:flutter/material.dart';
 
 import '../analytics/constants.dart' as analytics_constants;
@@ -526,9 +527,10 @@ final trackRebuildWidgets = ToggleableServiceExtensionDescription<bool>._(
   gaItem: analytics_constants.trackRebuildWidgets,
 );
 
-// This extension should never be displayed as a button so does not need a
-// ServiceExtensionDescription object.
+// This extensions below should never be displayed as a button so does not need
+// a ServiceExtensionDescription object.
 const String didSendFirstFrameEvent = 'ext.flutter.didSendFirstFrameEvent';
+const String memoryLeakTracking = memoryLeakTrackingExtensionName;
 
 final List<ServiceExtensionDescription> _extensionDescriptions = [
   debugPaint,

packages/devtools_shared/lib/devtools_shared.dart

@@ -8,5 +8,6 @@ export 'src/memory/class_heap_detail_stats.dart';
 export 'src/memory/event_sample.dart';
 export 'src/memory/heap_sample.dart';
 export 'src/memory/heap_space.dart';
+export 'src/memory/leaks/constants.dart';
 export 'src/memory/memory_json.dart';
 export 'src/service_utils.dart';

packages/devtools_shared/lib/src/memory/leaks/README.md

@@ -0,0 +1,2 @@
+Code in this folder will be moved to Dart SDK and/or Flutter framework after piloting the feature.
+See https://github.com/flutter/devtools/issues/3951.

packages/devtools_shared/lib/src/memory/leaks/constants.dart

@@ -0,0 +1,6 @@
+// Copyright 2021 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/// Name of extension that enables leak tracking for applications.
+const memoryLeakTrackingExtensionName = 'ext.dart.memoryLeakTracking';