A comment in the SpriteView source states that the animation

should not run when the window is minimized, nor in the middle
of a minimize animation; it refers to http://crbug.com/350329
as the bug related to fixing this problem. However, although the
SpriteView registers for the NSWindowWillMiniaturizeNotification it
doesn't check for its occurrence, and so does not actually recognize
when a window is being minimized. As a result, the SpriteView's
animation continues running when its window is miniaturized.

This change adds a check for NSWindowWillMiniaturizeNotification and
stops the animation when caught. This change also adds a unit test to
confirm that the animation stops on window miniaturization.

My SpinnerView class was based on SpriteView, which is how I
discovered this bug. The fix and unit test both come from SpinnerView.

BUG=472836

Review URL: https://codereview.chromium.org/1052973004

Cr-Commit-Position: refs/heads/master@{#323963}

chrome/browser/ui/cocoa/sprite_view.mm

@@ -73,10 +73,13 @@ static const CGFloat kFrameDuration = 0.03;  // 30ms for each animation frame.
     // Only animate the sprites if we are attached to a window, and that window
     // is not currently minimized or in the middle of a minimize animation.
     // http://crbug.com/350329
-    if ([self window] && ![[self window] isMiniaturized]) {
-      if ([imageLayer_ animationForKey:[spriteAnimation_ keyPath]] == nil)
+    if ([self window] && ![[self window] isMiniaturized] &&
+        ![[notification name] isEqualToString:
+             NSWindowWillMiniaturizeNotification]) {
+      if ([imageLayer_ animationForKey:[spriteAnimation_ keyPath]] == nil) {
         [imageLayer_ addAnimation:spriteAnimation_.get()
                      forKey:[spriteAnimation_ keyPath]];
+      }
     } else {
       [imageLayer_ removeAnimationForKey:[spriteAnimation_ keyPath]];
     }

chrome/browser/ui/cocoa/sprite_view_unittest.mm

@@ -13,6 +13,20 @@
 #include "ui/gfx/image/image.h"
 #include "ui/resources/grit/ui_resources.h"
 
+@interface SpriteView (ExposedForTesting)
+
+- (BOOL)isAnimating;
+
+@end
+
+@implementation SpriteView (ExposedForTesting)
+
+- (BOOL)isAnimating {
+  return [imageLayer_ animationForKey:[spriteAnimation_ keyPath]] != nil;
+}
+
+@end
+
 namespace {
 
 class SpriteViewTest : public CocoaTest {
@@ -41,4 +55,25 @@ TEST_F(SpriteViewTest, TestViewFrame) {
   EXPECT_EQ(imageSize.height, NSHeight(frame));
 }
 
+TEST_F(SpriteViewTest, StopAnimationOnMiniaturize) {
+  EXPECT_TRUE([view_ isAnimating]);
+
+  [test_window() miniaturize:nil];
+  EXPECT_FALSE([view_ isAnimating]);
+
+  [test_window() deminiaturize:nil];
+  EXPECT_TRUE([view_ isAnimating]);
+}
+
+TEST_F(SpriteViewTest,
+       StopAnimationOnRemoveFromSuperview) {
+  EXPECT_TRUE([view_ isAnimating]);
+
+  [view_ removeFromSuperview];
+  EXPECT_FALSE([view_ isAnimating]);
+
+  [[test_window() contentView] addSubview:view_];
+  EXPECT_TRUE([view_ isAnimating]);
+}
+
 }  // namespace