Upstream iOS UI utilities.

ios/chrome/browser/ui/animation_util.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef IOS_CHROME_BROWSER_UI_ANIMATION_UTIL_H_
+#define IOS_CHROME_BROWSER_UI_ANIMATION_UTIL_H_
+
+#import <UIKit/UIKit.h>
+
+// Animations returned by these utility methods use kCAFillModeBoth and aren't
+// automatically removed from the layer when finished.  Remove the animations
+// by calling |RemoveAnimationsFromLayers| in CATransaction completion blocks.
+// This is done so the effects of animations that finish earlier persist until
+// all animations in the transaction are finished.
+
+// Returns an animation that will animate |layer| from |beginFrame| to
+// |endFrame|.
+CAAnimation* FrameAnimationMake(CALayer* layer,
+                                CGRect beginFrame,
+                                CGRect endFrame);
+
+// Returns an animation that will animate the "opacity" property of a layer from
+// |beginOpacity| to |endOpacity|.
+CAAnimation* OpacityAnimationMake(CGFloat beginOpacity, CGFloat endOpacity);
+
+// Returns an animation group containing the animations in |animations| that has
+// the shortest duration necessary for all the animations to finish.
+CAAnimation* AnimationGroupMake(NSArray* animations);
+
+// Returns an animation that performs |animation| after |delay|.
+CAAnimation* DelayedAnimationMake(CAAnimation* animation, CFTimeInterval delay);
+
+// If |animation| is a CAAnimationGroup, searches its animations for a
+// CABasicAnimation for |keyPath|.  If |animation| is a CABasicAnimation, it
+// will check its keyPath against |keyPath|.
+CABasicAnimation* FindAnimationForKeyPath(NSString* keyPath,
+                                          CAAnimation* animation);
+
+// Removes the animation for |key| from each CALayer in |layers|.
+void RemoveAnimationForKeyFromLayers(NSString* key, NSArray* layers);
+
+#endif  // IOS_CHROME_BROWSER_UI_ANIMATION_UTIL_H_