[Mac] Display a quick animation when a popup is blocked so the user notices it in the Omnibox.

chrome/browser/cocoa/animatable_image.h

+// Copyright (c) 2010 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 CHROME_BROWSER_COCOA_ANIMATABLE_IMAGE_H_
+#define CHROME_BROWSER_COCOA_ANIMATABLE_IMAGE_H_
+
+#import <Cocoa/Cocoa.h>
+#import <QuartzCore/QuartzCore.h>
+
+#include "base/scoped_nsobject.h"
+
+// This class helps animate an NSImage's frame and opacity. It works by creating
+// a blank NSWindow in the size specified and giving it a layer on which the
+// image can be animated. Clients are free to embed this object as a child
+// window for easier window management. This class will clean itself up when
+// the animation has finished. Clients that install this as a child window
+// should listen for the NSWindowWillCloseNotification to perform any additional
+// cleanup.
+@interface AnimatableImage : NSWindow {
+ @private
+  // The image to animate.
+  scoped_nsobject<NSImage> image_;
+
+  // The frame of the image before and after the animation. This is in this
+  // window's coordinate system.
+  CGRect startFrame_;
+  CGRect endFrame_;
+
+  // Opacity values for the animation.
+  CGFloat startOpacity_;
+  CGFloat endOpacity_;
+
+  // The amount of time it takes to animate the image.
+  CGFloat duration_;
+}
+
+@property (nonatomic) CGRect startFrame;
+@property (nonatomic) CGRect endFrame;
+@property (nonatomic) CGFloat startOpacity;
+@property (nonatomic) CGFloat endOpacity;
+@property (nonatomic) CGFloat duration;
+
+// Designated initializer. Do not use any other NSWindow initializers. Creates
+// but does not show the blank animation window of the given size. The
+// |animationFrame| should usually be big enough to contain the |startFrame|
+// and |endFrame| properties of the animation.
+- (id)initWithImage:(NSImage*)image
+     animationFrame:(NSRect)animationFrame;
+
+// Begins the animation.
+- (void)startAnimation;
+
+@end
+
+#endif  // CHROME_BROWSER_COCOA_ANIMATABLE_IMAGE_H_