Use ScopedTaskEnvironment instead of MessageLoop in components unit tests.

components/autofill/core/browser/autofill_manager_unittest.cc

Index: components/autofill/core/browser/autofill_manager_unittest.cc
diff --git a/components/autofill/core/browser/autofill_manager_unittest.cc b/components/autofill/core/browser/autofill_manager_unittest.cc
index bb2f21b3adbd73cbd98373cbb3c4f227021e4381..f8cc2e3aba6bf2c6d8b43bdc831eeea7abc7d3c8 100644
--- a/components/autofill/core/browser/autofill_manager_unittest.cc
+++ b/components/autofill/core/browser/autofill_manager_unittest.cc
@@ -28,6 +28,7 @@
 #include "base/strings/utf_string_conversions.h"
 #include "base/test/histogram_tester.h"
 #include "base/test/scoped_feature_list.h"
+#include "base/test/scoped_task_environment.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
@@ -1107,7 +1108,7 @@ class AutofillManagerTest : public testing::Test {
   }
 
  protected:
-  base::MessageLoop message_loop_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
   MockAutofillClient autofill_client_;
   std::unique_ptr<MockAutofillDriver> autofill_driver_;
   std::unique_ptr<TestAutofillManager> autofill_manager_;