Use ScopedTaskEnvironment instead of MessageLoopForUI in chrome tests.

chrome/browser/extensions/api/image_writer_private/image_writer_private_apitest.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "base/message_loop/message_loop.h"
+#include "base/test/scoped_task_environment.h"
 #include "build/build_config.h"
 #include "chrome/browser/extensions/api/file_system/file_system_api.h"
 #include "chrome/browser/extensions/api/image_writer_private/operation.h"
 #include "chrome/browser/extensions/api/image_writer_private/removable_storage_provider.h"
 #include "chrome/browser/extensions/api/image_writer_private/test_utils.h"
 #include "chrome/browser/extensions/extension_apitest.h"
 #include "chrome/common/extensions/api/image_writer_private.h"
 #include "content/public/browser/browser_thread.h"
 
 namespace extensions {
 
 using api::image_writer_private::RemovableStorageDevice;
 using extensions::image_writer::FakeImageWriterClient;
 
 class ImageWriterPrivateApiTest : public ExtensionApiTest {
  public:
+  ImageWriterPrivateApiTest()
+      : scoped_task_environment_(
+            base::test::ScopedTaskEnvironment::MainThreadType::UI) {}
+
   void SetUpInProcessBrowserTestFixture() override {
     ExtensionApiTest::SetUpInProcessBrowserTestFixture();
     test_utils_.SetUp(true);
 
     ASSERT_TRUE(test_utils_.FillFile(test_utils_.GetImagePath(),
                                      image_writer::kImagePattern,
                                      image_writer::kTestFileSize));
     ASSERT_TRUE(test_utils_.FillFile(test_utils_.GetDevicePath(),
                                      image_writer::kDevicePattern,
                                      image_writer::kTestFileSize));
@@ skipping 50 matching lines @@
         base::BindOnce(&FakeImageWriterClient::Progress,
                        test_utils_.GetUtilityClient(), 100));
     content::BrowserThread::PostTask(
         content::BrowserThread::FILE, FROM_HERE,
         base::BindOnce(&FakeImageWriterClient::Success,
                        test_utils_.GetUtilityClient()));
   }
 #endif
 
  protected:
-  base::MessageLoopForUI message_loop_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
   image_writer::ImageWriterTestUtils test_utils_;
 };
 
 IN_PROC_BROWSER_TEST_F(ImageWriterPrivateApiTest, TestListDevices) {
   ASSERT_TRUE(RunExtensionTest("image_writer_private/list_devices"))
       << message_;
 }
 
 IN_PROC_BROWSER_TEST_F(ImageWriterPrivateApiTest, TestWriteFromFile) {
   FileSystemChooseEntryFunction::RegisterTempExternalFileSystemForTest(
@@ skipping 10 matching lines @@
   test_utils_.GetUtilityClient()->SetVerifyCallback(base::Bind(
       &ImageWriterPrivateApiTest::ImageWriterUtilityClientCall,
       base::Unretained(this)));
 #endif
 
   ASSERT_TRUE(RunPlatformAppTest("image_writer_private/write_from_file"))
       << message_;
 }
 
 }  // namespace extensions