Instrumented PipelineOwner for leak tracking (#137494)

Author: droidbg

packages/flutter/lib/src/rendering/object.dart

@@ -895,7 +895,17 @@ class PipelineOwner with DiagnosticableTreeMixin {
     this.onSemanticsOwnerCreated,
     this.onSemanticsUpdate,
     this.onSemanticsOwnerDisposed,
-  });
+  }){
+    // TODO(polina-c): stop duplicating code across disposables
+    // https://github.com/flutter/flutter/issues/137435
+    if (kFlutterMemoryAllocationsEnabled) {
+      MemoryAllocations.instance.dispatchObjectCreated(
+        library: 'package:flutter/rendering.dart',
+        className: '$PipelineOwner',
+        object: this,
+      );
+    }
+  }
 
   /// Called when a render object associated with this pipeline owner wishes to
   /// update its visual appearance.
@@ -1433,6 +1443,9 @@ class PipelineOwner with DiagnosticableTreeMixin {
     assert(rootNode == null);
     assert(_manifold == null);
     assert(_debugParent == null);
+    if (kFlutterMemoryAllocationsEnabled) {
+      MemoryAllocations.instance.dispatchObjectDisposed(object: this);
+    }
     _semanticsOwner?.dispose();
     _semanticsOwner = null;
     _nodesNeedingLayout.clear();

packages/flutter/test/rendering/object_test.dart

@@ -8,12 +8,20 @@ import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:leak_tracker_flutter_testing/leak_tracker_flutter_testing.dart';
 
 import 'rendering_tester.dart';
 
 void main() {
   TestRenderingFlutterBinding.ensureInitialized();
 
+  test('PipelineOwner dispatches memory events', () async {
+    await expectLater(
+      await memoryEvents(() => PipelineOwner().dispose(), PipelineOwner),
+      areCreateAndDispose,
+    );
+  });
+
   test('ensure frame is scheduled for markNeedsSemanticsUpdate', () {
     // Initialize all bindings because owner.flushSemantics() requires a window
     final TestRenderObject renderObject = TestRenderObject();