Address code review comments.

Author: a-siva

shell/common/fixtures/shell_test.dart

@@ -214,7 +214,7 @@ void performanceModeImpactsNotifyIdle() {
 
 @pragma('vm:entry-point')
 void callNotifyDestroyed() {
-  notifyDestroyedBool();
+  notifyDestroyed();
 }
 
 @pragma('vm:external-name', 'NotifyMessage')
@@ -429,8 +429,8 @@ Future<void> runCallback(IsolateParam param) async {
 @pragma('vm:entry-point')
 @pragma('vm:external-name', 'NotifyNativeBool')
 external void notifyNativeBool(bool value);
-@pragma('vm:external-name', 'NotifyDestroyedBool')
-external void notifyDestroyedBool();
+@pragma('vm:external-name', 'NotifyDestroyed')
+external void notifyDestroyed();
 
 @pragma('vm:entry-point')
 Future<void> testPluginUtilitiesCallbackHandle() async {

shell/common/shell.cc

@@ -851,6 +851,14 @@ void Shell::OnPlatformViewDestroyed() {
   // This incorrect assumption can lead to deadlock.
   rasterizer_->DisableThreadMergerIfNeeded();
 
+  // Notify the Dart VM that the PlatformView has been destroyed and some
+  // cleanup activity can be done (e.g: garbage collect the Dart heap).
+  task_runners_.GetUITaskRunner()->PostTask([engine = engine_->GetWeakPtr()]() {
+    if (engine) {
+      engine->NotifyDestroyed();
+    }
+  });
+
   // Note:
   // This is a synchronous operation because certain platforms depend on
   // setup/suspension of all activities that may be interacting with the GPU in
@@ -899,12 +907,6 @@ void Shell::OnPlatformViewDestroyed() {
   // Overall, the longer term plan is to remove this implementation once
   // https://github.com/flutter/flutter/issues/96679 is fixed.
   rasterizer_->TeardownExternalViewEmbedder();
-
-  task_runners_.GetUITaskRunner()->PostTask([engine = engine_->GetWeakPtr()]() {
-    if (engine) {
-      engine->NotifyDestroyed();
-    }
-  });
 }
 
 // |PlatformView::Delegate|

shell/common/shell_unittests.cc

@@ -3948,7 +3948,7 @@ TEST_F(ShellTest, NotifyDestroyed) {
   ASSERT_TRUE(ValidateShell(shell.get()));
 
   fml::CountDownLatch latch(1);
-  AddNativeCallback("NotifyDestroyedBool", CREATE_NATIVE_ENTRY([&](auto args) {
+  AddNativeCallback("NotifyDestroyed", CREATE_NATIVE_ENTRY([&](auto args) {
                       auto runtime_controller = const_cast<RuntimeController*>(
                           shell->GetEngine()->GetRuntimeController());
                       bool success = runtime_controller->NotifyDestroyed();