Revert "Use TaskScheduler instead of WorkerPool in x11_hotplug_event_handler.cc."

ui/compositor/test/test_suite.h

Index: ui/compositor/test/test_suite.h
diff --git a/ui/compositor/test/test_suite.h b/ui/compositor/test/test_suite.h
index 5bc015c7f39485d2dd0f5a7048486015b832b6b4..09ab669bfd2afdcdcb83b5a9bc3781e3d7e77899 100644
--- a/ui/compositor/test/test_suite.h
+++ b/ui/compositor/test/test_suite.h
@@ -12,9 +12,7 @@
 #include "base/test/test_suite.h"
 
 namespace base {
-namespace test {
-class ScopedTaskEnvironment;
-}
+class MessageLoop;
 }
 
 namespace ui {
@@ -31,7 +29,7 @@ class CompositorTestSuite : public base::TestSuite {
   void Shutdown() override;
 
  private:
-  std::unique_ptr<base::test::ScopedTaskEnvironment> scoped_task_environment_;
+  std::unique_ptr<base::MessageLoop> message_loop_;
 
   DISALLOW_COPY_AND_ASSIGN(CompositorTestSuite);
 };