Revert "Revert "Migrate flutter_runner from flutter_runner::{Thread,Loop} to fml::{Thread,MessageLoop} (flutter#15118)" (flutter#15903)"

This reverts commit 69bc783.

Author: Hunter Freyer

ci/licenses_golden/licenses_flutter

@@ -1306,8 +1306,6 @@ FILE: ../../../flutter/shell/platform/fuchsia/flutter/keyboard.cc
 FILE: ../../../flutter/shell/platform/fuchsia/flutter/keyboard.h
 FILE: ../../../flutter/shell/platform/fuchsia/flutter/keyboard_unittest.cc
 FILE: ../../../flutter/shell/platform/fuchsia/flutter/logging.h
-FILE: ../../../flutter/shell/platform/fuchsia/flutter/loop.cc
-FILE: ../../../flutter/shell/platform/fuchsia/flutter/loop.h
 FILE: ../../../flutter/shell/platform/fuchsia/flutter/main.cc
 FILE: ../../../flutter/shell/platform/fuchsia/flutter/meta/aot_product_runtime
 FILE: ../../../flutter/shell/platform/fuchsia/flutter/meta/aot_runtime
@@ -1331,12 +1329,6 @@ FILE: ../../../flutter/shell/platform/fuchsia/flutter/session_connection.cc
 FILE: ../../../flutter/shell/platform/fuchsia/flutter/session_connection.h
 FILE: ../../../flutter/shell/platform/fuchsia/flutter/surface.cc
 FILE: ../../../flutter/shell/platform/fuchsia/flutter/surface.h
-FILE: ../../../flutter/shell/platform/fuchsia/flutter/task_observers.cc
-FILE: ../../../flutter/shell/platform/fuchsia/flutter/task_observers.h
-FILE: ../../../flutter/shell/platform/fuchsia/flutter/task_runner_adapter.cc
-FILE: ../../../flutter/shell/platform/fuchsia/flutter/task_runner_adapter.h
-FILE: ../../../flutter/shell/platform/fuchsia/flutter/thread.cc
-FILE: ../../../flutter/shell/platform/fuchsia/flutter/thread.h
 FILE: ../../../flutter/shell/platform/fuchsia/flutter/unique_fdio_ns.h
 FILE: ../../../flutter/shell/platform/fuchsia/flutter/vsync_recorder.cc
 FILE: ../../../flutter/shell/platform/fuchsia/flutter/vsync_recorder.h

fml/thread.cc

@@ -86,8 +86,7 @@ void Thread::SetCurrentThreadName(const std::string& name) {
                    reinterpret_cast<DWORD_PTR*>(&info));
   } __except (EXCEPTION_CONTINUE_EXECUTION) {
   }
-#elif defined(OS_FUCHSIA)
-  zx::thread::self()->set_property(ZX_PROP_NAME, name.c_str(), name.size());
+
 #else
   FML_DLOG(INFO) << "Could not set the thread name to '" << name
                  << "' on this platform.";

shell/platform/fuchsia/flutter/BUILD.gn

@@ -66,8 +66,6 @@ template("runner_sources") {
       "keyboard.cc",
       "keyboard.h",
       "logging.h",
-      "loop.cc",
-      "loop.h",
       "platform_view.cc",
       "platform_view.h",
       "runner.cc",
@@ -76,12 +74,6 @@ template("runner_sources") {
       "session_connection.h",
       "surface.cc",
       "surface.h",
-      "task_observers.cc",
-      "task_observers.h",
-      "task_runner_adapter.cc",
-      "task_runner_adapter.h",
-      "thread.cc",
-      "thread.h",
       "unique_fdio_ns.h",
       "vsync_recorder.cc",
       "vsync_recorder.h",

shell/platform/fuchsia/flutter/component.cc

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#define FML_USED_ON_EMBEDDER
+
 #include "component.h"
 
 #include <dlfcn.h>
@@ -37,9 +39,6 @@
 #include "runtime/dart/utils/tempfs.h"
 #include "runtime/dart/utils/vmo.h"
 
-#include "task_observers.h"
-#include "task_runner_adapter.h"
-
 // TODO(kaushikiska): Use these constants from ::llcpp::fuchsia::io
 // Can read from target object.
 constexpr uint32_t OPEN_RIGHT_READABLE = 1u;
@@ -186,11 +185,11 @@ ActiveApplication Application::Create(
     fuchsia::sys::StartupInfo startup_info,
     std::shared_ptr<sys::ServiceDirectory> runner_incoming_services,
     fidl::InterfaceRequest<fuchsia::sys::ComponentController> controller) {
-  std::unique_ptr<Thread> thread = std::make_unique<Thread>();
+  std::unique_ptr<fml::Thread> thread = std::make_unique<fml::Thread>();
   std::unique_ptr<Application> application;
 
   fml::AutoResetWaitableEvent latch;
-  async::PostTask(thread->dispatcher(), [&]() mutable {
+  fml::TaskRunner::RunNowOrPostTask(thread->GetTaskRunner(), [&]() mutable {
     application.reset(
         new Application(std::move(termination_callback), std::move(package),
                         std::move(startup_info), runner_incoming_services,
@@ -490,12 +489,12 @@ Application::Application(
   // terminates.
   settings_.leak_vm = false;
 
-  settings_.task_observer_add =
-      std::bind(&CurrentMessageLoopAddAfterTaskObserver, std::placeholders::_1,
-                std::placeholders::_2);
-
-  settings_.task_observer_remove = std::bind(
-      &CurrentMessageLoopRemoveAfterTaskObserver, std::placeholders::_1);
+  settings_.task_observer_add = [](intptr_t key, fml::closure callback) {
+    fml::MessageLoop::GetCurrent().AddTaskObserver(key, std::move(callback));
+  };
+  settings_.task_observer_remove = [](intptr_t key) {
+    fml::MessageLoop::GetCurrent().RemoveTaskObserver(key);
+  };
 
   settings_.dart_flags = {"--no_causal_async_stacks", "--lazy_async_stacks"};
 
@@ -509,8 +508,7 @@ Application::Application(
 #endif  // defined(__aarch64__)
 
   auto weak_application = weak_factory_.GetWeakPtr();
-  auto platform_task_runner =
-      CreateFMLTaskRunner(async_get_default_dispatcher());
+  auto platform_task_runner = fml::MessageLoop::GetCurrent().GetTaskRunner();
   const std::string component_url = package.resolved_url;
   settings_.unhandled_exception_callback = [weak_application,
                                             platform_task_runner,

shell/platform/fuchsia/flutter/component.h

@@ -23,18 +23,18 @@
 
 #include "flutter/common/settings.h"
 #include "flutter/fml/macros.h"
+#include "flutter/fml/thread.h"
 
 #include "engine.h"
 #include "flutter_runner_product_configuration.h"
-#include "thread.h"
 #include "unique_fdio_ns.h"
 
 namespace flutter_runner {
 
 class Application;
 
 struct ActiveApplication {
-  std::unique_ptr<Thread> thread;
+  std::unique_ptr<fml::Thread> thread;
   std::unique_ptr<Application> application;
 
   ActiveApplication& operator=(ActiveApplication&& other) noexcept {

shell/platform/fuchsia/flutter/engine.cc

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#define FML_USED_ON_EMBEDDER
+
 #include "engine.h"
 
 #include <lib/async/cpp/task.h>
@@ -24,7 +26,6 @@
 #include "fuchsia_intl.h"
 #include "platform_view.h"
 #include "surface.h"
-#include "task_runner_adapter.h"
 
 #if defined(LEGACY_FUCHSIA_EMBEDDER)
 #include "compositor_context.h"  // nogncheck
@@ -71,28 +72,17 @@ Engine::Engine(Delegate& delegate,
                FlutterRunnerProductConfiguration product_config)
     : delegate_(delegate),
       thread_label_(std::move(thread_label)),
-#if defined(LEGACY_FUCHSIA_EMBEDDER)
-      use_legacy_renderer_(product_config.use_legacy_renderer()),
-#endif
-      intercept_all_input_(product_config.get_intercept_all_input()),
+      thread_host_(thread_label_ + ".",
+                   flutter::ThreadHost::Type::IO |
+                       flutter::ThreadHost::Type::UI |
+                       flutter::ThreadHost::Type::GPU),
       weak_factory_(this) {
   if (zx::event::create(0, &vsync_event_) != ZX_OK) {
     FML_DLOG(ERROR) << "Could not create the vsync event.";
     return;
   }
 
-  // Get the task runners from the managed threads. The current thread will be
-  // used as the "platform" thread.
-  const flutter::TaskRunners task_runners(
-      thread_label_,  // Dart thread labels
-      CreateFMLTaskRunner(async_get_default_dispatcher()),  // platform
-      CreateFMLTaskRunner(threads_[0].dispatcher()),        // raster
-      CreateFMLTaskRunner(threads_[1].dispatcher()),        // ui
-      CreateFMLTaskRunner(threads_[2].dispatcher())         // io
-  );
-  UpdateNativeThreadLabelNames(thread_label_, task_runners);
-
-  // Connect to Scenic.
+  // Set up the session connection.
   auto scenic = svc->Connect<fuchsia::ui::scenic::Scenic>();
   fidl::InterfaceHandle<fuchsia::ui::scenic::Session> session;
   fidl::InterfaceHandle<fuchsia::ui::scenic::SessionListener> session_listener;
@@ -274,6 +264,34 @@ Engine::Engine(Delegate& delegate,
                 vsync_handle);
           });
 
+  // Session can be terminated on the GPU thread, but we must terminate
+  // ourselves on the platform thread.
+  //
+  // This handles the fidl error callback when the Session connection is
+  // broken. The SessionListener interface also has an OnError method, which is
+  // invoked on the platform thread (in PlatformView).
+  fml::closure on_session_error_callback =
+      [dispatcher = async_get_default_dispatcher(),
+       weak = weak_factory_.GetWeakPtr()]() {
+        async::PostTask(dispatcher, [weak]() {
+          if (weak) {
+            weak->Terminate();
+          }
+        });
+      };
+
+  // Get the task runners from the managed threads. The current thread will be
+  // used as the "platform" thread.
+  fml::MessageLoop::EnsureInitializedForCurrentThread();
+
+  const flutter::TaskRunners task_runners(
+      thread_label_,                                   // Dart thread labels
+      fml::MessageLoop::GetCurrent().GetTaskRunner(),  // platform
+      thread_host_.gpu_thread->GetTaskRunner(),        // gpu
+      thread_host_.ui_thread->GetTaskRunner(),         // ui
+      thread_host_.io_thread->GetTaskRunner()          // io
+  );
+
   // Setup the callback that will instantiate the rasterizer.
   flutter::Shell::CreateCallback<flutter::Rasterizer> on_create_rasterizer;
 #if defined(LEGACY_FUCHSIA_EMBEDDER)
@@ -454,12 +472,6 @@ Engine::Engine(Delegate& delegate,
 
 Engine::~Engine() {
   shell_.reset();
-  for (auto& thread : threads_) {
-    thread.Quit();
-  }
-  for (auto& thread : threads_) {
-    thread.Join();
-  }
 }
 
 std::optional<uint32_t> Engine::GetEngineReturnCode() const {

shell/platform/fuchsia/flutter/engine.h

@@ -23,9 +23,9 @@
 
 #include "flutter_runner_product_configuration.h"
 #include "fuchsia_external_view_embedder.h"
+#include "flutter/shell/common/thread_host.h"
 #include "isolate_configurator.h"
 #include "session_connection.h"
-#include "thread.h"
 #include "vulkan_surface_producer.h"
 
 #if defined(LEGACY_FUCHSIA_EMBEDDER)
@@ -71,8 +71,8 @@ class Engine final {
   Delegate& delegate_;
 
   const std::string thread_label_;
-  std::array<Thread, 3> threads_;
-
+  flutter::ThreadHost thread_host_;
+  
   std::optional<SessionConnection> session_connection_;
   std::optional<VulkanSurfaceProducer> surface_producer_;
   std::shared_ptr<FuchsiaExternalViewEmbedder> external_view_embedder_;

shell/platform/fuchsia/flutter/fuchsia_intl.cc

@@ -8,7 +8,6 @@
 #include <string>
 #include <vector>
 
-#include "loop.h"
 #include "rapidjson/document.h"
 #include "rapidjson/stringbuffer.h"
 #include "rapidjson/writer.h"