Adds ash_mus_unittests to FYI bot

ash/display/screen_ash_unittest.cc

Index: ash/display/screen_ash_unittest.cc
diff --git a/ash/display/screen_ash_unittest.cc b/ash/display/screen_ash_unittest.cc
index 4f02ab0f1c5783cde571364ddfdda45f5e2bbc6a..b89b437908a950d753d0021d19aa6c95ee450caa 100644
--- a/ash/display/screen_ash_unittest.cc
+++ b/ash/display/screen_ash_unittest.cc
@@ -6,18 +6,10 @@
 #include "ash/test/ash_test_base.h"
 #include "ui/aura/test/test_window_delegate.h"
 #include "ui/aura/window.h"
-#include "ui/display/manager/display_manager.h"
 
 namespace ash {
 
-class ScreenAshTest : public test::AshTestBase {
- public:
-  ScreenAshTest() {}
-  ~ScreenAshTest() override {}
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(ScreenAshTest);
-};
+using ScreenAshTest = test::AshTestBase;
 
 // Tests that ScreenAsh::GetWindowAtScreenPoint() returns the correct window on
 // the correct display.