Flip the flag to enable smooth screen rotation by default.

ash/rotator/screen_rotation_animator_unittest.cc

Index: ash/rotator/screen_rotation_animator_unittest.cc
diff --git a/ash/rotator/screen_rotation_animator_unittest.cc b/ash/rotator/screen_rotation_animator_unittest.cc
index 19de9cebb14f7c317448a2714d58e5395fa80edf..ee802ff03036b37f1205021c0074ee8c8801ed3b 100644
--- a/ash/rotator/screen_rotation_animator_unittest.cc
+++ b/ash/rotator/screen_rotation_animator_unittest.cc
@@ -163,6 +163,8 @@ void ScreenRotationAnimatorSlowAnimationTest::SetUp() {
     return;
   }
 
+  base::CommandLine::ForCurrentProcess()->AppendSwitch(
+      switches::kAshDisableSmoothScreenRotation);
   animator_ = base::MakeUnique<ScreenRotationAnimator>(display_.id());
   test_api_ =
       base::MakeUnique<test::ScreenRotationAnimatorTestApi>(animator_.get());
@@ -230,8 +232,6 @@ void ScreenRotationAnimatorSmoothAnimationTest::SetUp() {
     return;
   }
 
-  base::CommandLine::ForCurrentProcess()->AppendSwitch(
-      switches::kAshEnableSmoothScreenRotation);
   run_loop_ = base::MakeUnique<base::RunLoop>();
   SetScreenRotationAnimator(display_.id(), run_loop_->QuitWhenIdleClosure(),
                             run_loop_->QuitWhenIdleClosure());