Revert "Fix thread names + add test (#27897)"

This reverts commit 851eea5d2041c12df4f69e5a737aebcc45caf6d8.
diff --git a/shell/platform/fuchsia/flutter/BUILD.gn b/shell/platform/fuchsia/flutter/BUILD.gn
index c4d126e..70dae94 100644
--- a/shell/platform/fuchsia/flutter/BUILD.gn
+++ b/shell/platform/fuchsia/flutter/BUILD.gn
@@ -21,10 +21,6 @@
   enable_metal = false
 }
 
-config("runner_base_config") {
-  defines = [ "FML_USED_ON_EMBEDDER" ]
-}
-
 config("runner_debug_config") {
   defines = [ "DEBUG" ]  # Needed due to direct dart dependencies.
 }
@@ -40,7 +36,7 @@
 template("runner_sources") {
   assert(defined(invoker.product), "runner_sources must define product")
 
-  runner_configs = [ ":runner_base_config" ]
+  runner_configs = []
   if (is_debug) {
     runner_configs += [ ":runner_debug_config" ]
   }
diff --git a/shell/platform/fuchsia/flutter/component.cc b/shell/platform/fuchsia/flutter/component.cc
index c7efd20..3f75c3b 100644
--- a/shell/platform/fuchsia/flutter/component.cc
+++ b/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>
diff --git a/shell/platform/fuchsia/flutter/engine.cc b/shell/platform/fuchsia/flutter/engine.cc
index 502b799..350e0e4 100644
--- a/shell/platform/fuchsia/flutter/engine.cc
+++ b/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>
@@ -41,13 +43,6 @@
 
 }  // namespace
 
-flutter::ThreadHost Engine::CreateThreadHost(const std::string& name_prefix) {
-  fml::Thread::SetCurrentThreadName(name_prefix + ".platform");
-  return flutter::ThreadHost(name_prefix, flutter::ThreadHost::Type::RASTER |
-                                              flutter::ThreadHost::Type::UI |
-                                              flutter::ThreadHost::Type::IO);
-}
-
 Engine::Engine(Delegate& delegate,
                std::string thread_label,
                std::shared_ptr<sys::ServiceDirectory> svc,
@@ -60,7 +55,10 @@
                FlutterRunnerProductConfiguration product_config)
     : delegate_(delegate),
       thread_label_(std::move(thread_label)),
-      thread_host_(CreateThreadHost(thread_label_)),
+      thread_host_(thread_label_ + ".",
+                   flutter::ThreadHost::Type::RASTER |
+                       flutter::ThreadHost::Type::UI |
+                       flutter::ThreadHost::Type::IO),
       intercept_all_input_(product_config.get_intercept_all_input()),
       weak_factory_(this) {
   // Get the task runners from the managed threads. The current thread will be
diff --git a/shell/platform/fuchsia/flutter/engine.h b/shell/platform/fuchsia/flutter/engine.h
index 5108b03..bc7a66f 100644
--- a/shell/platform/fuchsia/flutter/engine.h
+++ b/shell/platform/fuchsia/flutter/engine.h
@@ -45,8 +45,6 @@
     virtual void OnEngineTerminate(const Engine* holder) = 0;
   };
 
-  static flutter::ThreadHost CreateThreadHost(const std::string& name_prefix);
-
   Engine(Delegate& delegate,
          std::string thread_label,
          std::shared_ptr<sys::ServiceDirectory> svc,
diff --git a/shell/platform/fuchsia/flutter/main.cc b/shell/platform/fuchsia/flutter/main.cc
index cd34ab8..d5bfebb 100644
--- a/shell/platform/fuchsia/flutter/main.cc
+++ b/shell/platform/fuchsia/flutter/main.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 <lib/async-loop/cpp/loop.h>
 #include <lib/sys/inspect/cpp/component.h>
 #include <lib/trace-provider/provider.h>
diff --git a/shell/platform/fuchsia/flutter/tests/engine_unittests.cc b/shell/platform/fuchsia/flutter/tests/engine_unittests.cc
index 534aa6a..b077878 100644
--- a/shell/platform/fuchsia/flutter/tests/engine_unittests.cc
+++ b/shell/platform/fuchsia/flutter/tests/engine_unittests.cc
@@ -12,7 +12,6 @@
 #include "flutter/fml/message_loop_impl.h"
 #include "flutter/fml/task_runner.h"
 #include "flutter/shell/common/serialization_callbacks.h"
-#include "flutter/shell/common/thread_host.h"
 #include "flutter/shell/platform/fuchsia/flutter/gfx_session_connection.h"
 #include "flutter/shell/platform/fuchsia/flutter/logging.h"
 #include "flutter/shell/platform/fuchsia/flutter/runner.h"
@@ -26,13 +25,6 @@
 
 namespace flutter_runner {
 namespace testing {
-namespace {
-
-std::string GetCurrentTestName() {
-  return ::testing::UnitTest::GetInstance()->current_test_info()->name();
-}
-
-}  // namespace
 
 class MockTaskRunner : public fml::BasicTaskRunner {
  public:
@@ -91,41 +83,6 @@
   std::optional<scenic::Session> session_;
 };
 
-TEST_F(EngineTest, ThreadNames) {
-  std::string prefix = GetCurrentTestName();
-  flutter::ThreadHost engine_thread_host = Engine::CreateThreadHost(prefix);
-
-  char thread_name[ZX_MAX_NAME_LEN];
-  zx::thread::self()->get_property(ZX_PROP_NAME, thread_name,
-                                   sizeof(thread_name));
-  EXPECT_EQ(std::string(thread_name), prefix + std::string(".platform"));
-  EXPECT_EQ(engine_thread_host.platform_thread, nullptr);
-
-  engine_thread_host.raster_thread->GetTaskRunner()->PostTask([&prefix]() {
-    char thread_name[ZX_MAX_NAME_LEN];
-    zx::thread::self()->get_property(ZX_PROP_NAME, thread_name,
-                                     sizeof(thread_name));
-    EXPECT_EQ(std::string(thread_name), prefix + std::string(".raster"));
-  });
-  engine_thread_host.raster_thread->Join();
-
-  engine_thread_host.ui_thread->GetTaskRunner()->PostTask([&prefix]() {
-    char thread_name[ZX_MAX_NAME_LEN];
-    zx::thread::self()->get_property(ZX_PROP_NAME, thread_name,
-                                     sizeof(thread_name));
-    EXPECT_EQ(std::string(thread_name), prefix + std::string(".ui"));
-  });
-  engine_thread_host.ui_thread->Join();
-
-  engine_thread_host.io_thread->GetTaskRunner()->PostTask([&prefix]() {
-    char thread_name[ZX_MAX_NAME_LEN];
-    zx::thread::self()->get_property(ZX_PROP_NAME, thread_name,
-                                     sizeof(thread_name));
-    EXPECT_EQ(std::string(thread_name), prefix + std::string(".io"));
-  });
-  engine_thread_host.io_thread->Join();
-}
-
 TEST_F(EngineTest, SkpWarmup) {
   SkISize draw_size = SkISize::Make(100, 100);
   SkPictureRecorder recorder;