Revert of [ObjC ARC] Converts ios/chrome/browser/ui:ui to ARC.

ios/chrome/browser/ui/animation_util.mm

Index: ios/chrome/browser/ui/animation_util.mm
diff --git a/ios/chrome/browser/ui/animation_util.mm b/ios/chrome/browser/ui/animation_util.mm
index 989791d366c585d69d01a95c7cf770505010af52..1878c3e7709240f1422a4bf076c56ab74db7e329 100644
--- a/ios/chrome/browser/ui/animation_util.mm
+++ b/ios/chrome/browser/ui/animation_util.mm
@@ -8,10 +8,6 @@
 #include <cmath>
 
 #include "ios/chrome/browser/ui/reversed_animation.h"
-
-#if !defined(__has_feature) || !__has_feature(objc_arc)
-#error "This file requires ARC support."
-#endif
 
 CAAnimation* FrameAnimationMake(CALayer* layer,
                                 CGRect beginFrame,
@@ -63,7 +59,7 @@
 
 CAAnimation* DelayedAnimationMake(CAAnimation* animation,
                                   CFTimeInterval delay) {
-  CAAnimation* delayedAnimation = [animation copy];
+  CAAnimation* delayedAnimation = [[animation copy] autorelease];
   if (delayedAnimation) {
     delayedAnimation.beginTime = delay;
     delayedAnimation = AnimationGroupMake(@[ delayedAnimation ]);