Run Dart VM tasks on the engine's ConcurrentMessageLoop instead the VM's separate thread pool.

Bug: dart-lang/sdk#44228

Author: rmacnak-google

runtime/dart_vm.cc

@@ -177,6 +177,14 @@ Dart_Handle GetVMServiceAssetsArchiveCallback() {
 #endif
 }
 
+void PostTaskCallback(void* post_task_data,
+                      Dart_Task task,
+                      Dart_TaskData task_data) {
+  auto* dart_vm = reinterpret_cast<DartVM*>(post_task_data);
+  dart_vm->GetConcurrentWorkerTaskRunner()->PostTask(
+      [task] { Dart_RunTask(task); });
+}
+
 static const char kStdoutStreamId[] = "Stdout";
 static const char kStderrStreamId[] = "Stderr";
 
@@ -449,6 +457,8 @@ DartVM::DartVM(std::shared_ptr<const DartVMData> vm_data,
     params.thread_exit = ThreadExitCallback;
     params.get_service_assets = GetVMServiceAssetsArchiveCallback;
     params.entropy_source = dart::bin::GetEntropy;
+    params.post_task = PostTaskCallback;
+    params.post_task_data = this;
     DartVMInitializer::Initialize(&params);
     // Send the earliest available timestamp in the application lifecycle to
     // timeline. The difference between this timestamp and the time we render
@@ -483,6 +493,10 @@ DartVM::DartVM(std::shared_ptr<const DartVMData> vm_data,
     Dart_SetDartLibrarySourcesKernel(dart_library_sources->GetMapping(),
                                      dart_library_sources->GetSize());
   }
+
+  // Update thread names now that the Dart VM is initialized.
+  concurrent_message_loop_->PostTaskToAllWorkers(
+      [] { Dart_SetThreadName("FlutterConcurrentMessageLoopWorker"); });
 }
 
 DartVM::~DartVM() {