Use OnceCallback on Mojo interfaces in //ash

ash/test/test_session_state_animator.h

Index: ash/test/test_session_state_animator.h
diff --git a/ash/test/test_session_state_animator.h b/ash/test/test_session_state_animator.h
index 7980c849125b490f3af0bc2d72717767df821fb3..8854cc9e39253a2d316f86f97d07785a09c40625 100644
--- a/ash/test/test_session_state_animator.h
+++ b/ash/test/test_session_state_animator.h
@@ -70,8 +70,9 @@ class TestSessionStateAnimator : public SessionStateAnimator {
   void StartAnimationWithCallback(int container_mask,
                                   AnimationType type,
                                   AnimationSpeed speed,
-                                  base::Closure callback) override;
-  AnimationSequence* BeginAnimationSequence(base::Closure callback) override;
+                                  base::OnceClosure callback) override;
+  AnimationSequence* BeginAnimationSequence(
+      base::OnceClosure callback) override;
   bool IsWallpaperHidden() const override;
   void ShowWallpaper() override;
   void HideWallpaper() override;