Revert "Enable shutting down all root isolates in a VM. (flutter#8402)…

…" (flutter#8431)

This reverts commit b59c443.

ci/licenses_golden/licenses_flutter

@@ -374,7 +374,6 @@ FILE: ../../../flutter/lib/ui/window/window.h
 FILE: ../../../flutter/runtime/dart_isolate.cc
 FILE: ../../../flutter/runtime/dart_isolate.h
 FILE: ../../../flutter/runtime/dart_isolate_unittests.cc
-FILE: ../../../flutter/runtime/dart_lifecycle_unittests.cc
 FILE: ../../../flutter/runtime/dart_service_isolate.cc
 FILE: ../../../flutter/runtime/dart_service_isolate.h
 FILE: ../../../flutter/runtime/dart_service_isolate_unittests.cc

common/settings.h

@@ -29,8 +29,6 @@ using UnhandledExceptionCallback =
 // callback that generates the mapping from these paths.
 // https://github.com/flutter/flutter/issues/26783
 using MappingCallback = std::function<std::unique_ptr<fml::Mapping>(void)>;
-using MappingsCallback =
-    std::function<std::vector<std::unique_ptr<const fml::Mapping>>(void)>;
 
 struct Settings {
   Settings();
@@ -55,10 +53,8 @@ struct Settings {
   MappingCallback dart_library_sources_kernel;
 
   std::string application_library_path;
-
-  std::string application_kernel_asset;       // deprecated
-  std::string application_kernel_list_asset;  // deprecated
-  MappingsCallback application_kernels;
+  std::string application_kernel_asset;
+  std::string application_kernel_list_asset;
 
   std::string temp_directory_path;
   std::vector<std::string> dart_flags;

runtime/BUILD.gn

@@ -101,17 +101,18 @@ test_fixtures("runtime_fixtures") {
   fixtures = [ "fixtures/simple_main.dart" ]
 }
 
-source_set("runtime_unittests_common") {
-  visibility = [ ":*" ]
-
+executable("runtime_unittests") {
   testonly = true
 
   sources = [
+    "dart_isolate_unittests.cc",
+    "dart_service_isolate_unittests.cc",
+    "dart_vm_unittests.cc",
     "runtime_test.cc",
     "runtime_test.h",
   ]
 
-  public_deps = [
+  deps = [
     ":libdart",
     ":runtime",
     ":runtime_fixtures",
@@ -123,36 +124,6 @@ source_set("runtime_unittests_common") {
     "//third_party/skia",
     "//third_party/tonic",
   ]
-}
-
-executable("runtime_unittests") {
-  testonly = true
-
-  sources = [
-    "dart_isolate_unittests.cc",
-    "dart_service_isolate_unittests.cc",
-    "dart_vm_unittests.cc",
-  ]
-
-  deps = [
-    ":runtime_unittests_common",
-  ]
-
-  if (is_linux) {
-    ldflags = [ "-rdynamic" ]
-  }
-}
-
-executable("runtime_lifecycle_unittests") {
-  testonly = true
-
-  sources = [
-    "dart_lifecycle_unittests.cc",
-  ]
-
-  deps = [
-    ":runtime_unittests_common",
-  ]
 
   if (is_linux) {
     ldflags = [ "-rdynamic" ]

runtime/dart_isolate.cc

@@ -162,8 +162,17 @@ bool DartIsolate::Initialize(Dart_Isolate dart_isolate, bool is_root_isolate) {
 
   tonic::DartIsolateScope scope(isolate());
 
-  SetMessageHandlingTaskRunner(GetTaskRunners().GetUITaskRunner(),
-                               is_root_isolate);
+  if (is_root_isolate) {
+    if (auto task_runner = GetTaskRunners().GetUITaskRunner()) {
+      // Isolates may not have any particular thread affinity. Only initialize
+      // the task dispatcher if a task runner is explicitly specified.
+      tonic::DartMessageHandler::TaskDispatcher dispatcher =
+          [task_runner](std::function<void()> task) {
+            task_runner->PostTask(task);
+          };
+      message_handler().Initialize(dispatcher);
+    }
+  }
 
   if (tonic::LogIfError(
           Dart_SetLibraryTagHandler(tonic::DartState::HandleLibraryTag))) {
@@ -178,23 +187,6 @@ bool DartIsolate::Initialize(Dart_Isolate dart_isolate, bool is_root_isolate) {
   return true;
 }
 
-fml::RefPtr<fml::TaskRunner> DartIsolate::GetMessageHandlingTaskRunner() const {
-  return message_handling_task_runner_;
-}
-
-void DartIsolate::SetMessageHandlingTaskRunner(
-    fml::RefPtr<fml::TaskRunner> runner,
-    bool is_root_isolate) {
-  if (!is_root_isolate || !runner) {
-    return;
-  }
-
-  message_handling_task_runner_ = runner;
-
-  message_handler().Initialize(
-      [runner](std::function<void()> task) { runner->PostTask(task); });
-}
-
 // Updating thread names here does not change the underlying OS thread names.
 // Instead, this is just additional metadata for the Observatory to show the
 // thread name of the isolate.
@@ -369,34 +361,6 @@ bool DartIsolate::PrepareForRunningFromKernel(
   return true;
 }
 
-FML_WARN_UNUSED_RESULT
-bool DartIsolate::PrepareForRunningFromKernels(
-    std::vector<std::shared_ptr<const fml::Mapping>> kernels) {
-  const auto count = kernels.size();
-  if (count == 0) {
-    return false;
-  }
-
-  for (size_t i = 0; i < count; ++i) {
-    bool last = (i == (count - 1));
-    if (!PrepareForRunningFromKernel(kernels[i], last)) {
-      return false;
-    }
-  }
-
-  return true;
-}
-
-FML_WARN_UNUSED_RESULT
-bool DartIsolate::PrepareForRunningFromKernels(
-    std::vector<std::unique_ptr<const fml::Mapping>> kernels) {
-  std::vector<std::shared_ptr<const fml::Mapping>> shared_kernels;
-  for (auto& kernel : kernels) {
-    shared_kernels.emplace_back(std::move(kernel));
-  }
-  return PrepareForRunningFromKernels(shared_kernels);
-}
-
 bool DartIsolate::MarkIsolateRunnable() {
   TRACE_EVENT0("flutter", "DartIsolate::MarkIsolateRunnable");
   if (phase_ != Phase::LibrariesSetup) {
@@ -520,6 +484,7 @@ bool DartIsolate::Shutdown() {
     // the isolate to shutdown as a parameter.
     FML_DCHECK(Dart_CurrentIsolate() == nullptr);
     Dart_EnterIsolate(vm_isolate);
+    shutdown_callbacks_.clear();
     Dart_ShutdownIsolate();
     FML_DCHECK(Dart_CurrentIsolate() == nullptr);
   }
@@ -721,8 +686,6 @@ DartIsolate::CreateDartVMAndEmbedderObjectPair(
     }
   }
 
-  DartVMRef::GetRunningVM()->RegisterActiveIsolate(*embedder_isolate);
-
   // The ownership of the embedder object is controlled by the Dart VM. So the
   // only reference returned to the caller is weak.
   embedder_isolate.release();
@@ -731,9 +694,7 @@ DartIsolate::CreateDartVMAndEmbedderObjectPair(
 
 // |Dart_IsolateShutdownCallback|
 void DartIsolate::DartIsolateShutdownCallback(
-    std::shared_ptr<DartIsolate>* embedder_isolate) {
-  embedder_isolate->get()->OnShutdownCallback();
-}
+    std::shared_ptr<DartIsolate>* embedder_isolate) {}
 
 // |Dart_IsolateCleanupCallback|
 void DartIsolate::DartIsolateCleanupCallback(
@@ -758,12 +719,6 @@ void DartIsolate::AddIsolateShutdownCallback(fml::closure closure) {
       std::make_unique<AutoFireClosure>(std::move(closure)));
 }
 
-void DartIsolate::OnShutdownCallback() {
-  shutdown_callbacks_.clear();
-  DartVMRef::GetRunningVM()->UnregisterActiveIsolate(
-      std::static_pointer_cast<DartIsolate>(shared_from_this()));
-}
-
 DartIsolate::AutoFireClosure::AutoFireClosure(fml::closure closure)
     : closure_(std::move(closure)) {}
 

runtime/dart_isolate.h

@@ -5,7 +5,6 @@
 #ifndef FLUTTER_RUNTIME_DART_ISOLATE_H_
 #define FLUTTER_RUNTIME_DART_ISOLATE_H_
 
-#include <memory>
 #include <set>
 #include <string>
 
@@ -76,14 +75,6 @@ class DartIsolate : public UIDartState {
   bool PrepareForRunningFromKernel(std::shared_ptr<const fml::Mapping> kernel,
                                    bool last_piece = true);
 
-  FML_WARN_UNUSED_RESULT
-  bool PrepareForRunningFromKernels(
-      std::vector<std::shared_ptr<const fml::Mapping>> kernels);
-
-  FML_WARN_UNUSED_RESULT
-  bool PrepareForRunningFromKernels(
-      std::vector<std::unique_ptr<const fml::Mapping>> kernels);
-
   FML_WARN_UNUSED_RESULT
   bool Run(const std::string& entrypoint, fml::closure on_run = nullptr);
 
@@ -103,8 +94,6 @@ class DartIsolate : public UIDartState {
 
   std::weak_ptr<DartIsolate> GetWeakIsolatePtr();
 
-  fml::RefPtr<fml::TaskRunner> GetMessageHandlingTaskRunner() const;
-
  private:
   bool LoadKernel(std::shared_ptr<const fml::Mapping> mapping, bool last_piece);
 
@@ -127,14 +116,10 @@ class DartIsolate : public UIDartState {
   std::vector<std::shared_ptr<const fml::Mapping>> kernel_buffers_;
   std::vector<std::unique_ptr<AutoFireClosure>> shutdown_callbacks_;
   ChildIsolatePreparer child_isolate_preparer_ = nullptr;
-  fml::RefPtr<fml::TaskRunner> message_handling_task_runner_;
 
   FML_WARN_UNUSED_RESULT
   bool Initialize(Dart_Isolate isolate, bool is_root_isolate);
 
-  void SetMessageHandlingTaskRunner(fml::RefPtr<fml::TaskRunner> runner,
-                                    bool is_root_isolate);
-
   FML_WARN_UNUSED_RESULT
   bool LoadLibraries(bool is_root_isolate);
 
@@ -143,8 +128,6 @@ class DartIsolate : public UIDartState {
   FML_WARN_UNUSED_RESULT
   bool MarkIsolateRunnable();
 
-  void OnShutdownCallback();
-
   // |Dart_IsolateCreateCallback|
   static Dart_Isolate DartIsolateCreateCallback(
       const char* advisory_script_uri,