[Mac] Reimplement HoverButton and HoverImageButton using NSButton.state.

chrome/browser/ui/cocoa/hover_close_button.mm

 // Copyright (c) 2012 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.
 
 #import "chrome/browser/ui/cocoa/hover_close_button.h"
 
 #include "base/memory/scoped_nsobject.h"
 #include "base/memory/scoped_ptr.h"
 #include "grit/generated_resources.h"
 #include "grit/theme_resources.h"
@@ skipping 158 matching lines @@
       imageID = IDR_CLOSE_1_H;
       break;
     case kHoverStateMouseDown:
       imageID = IDR_CLOSE_1_P;
       break;
   }
   ui::ResourceBundle& bundle = ui::ResourceBundle::GetSharedInstance();
   return bundle.GetNativeImageNamed(imageID).ToNSImage();
 }
 
-- (void)setHoverState:(HoverState)state {
-  if (state != self.hoverState) {
-    previousState_ = self.hoverState;
-    [super setHoverState:state];
-    // Only animate the HoverStateNone case.
-    if (state == kHoverStateNone) {
-      DCHECK(fadeOutAnimation_ == nil);
-      fadeOutAnimation_ =
-          [[GTMKeyValueAnimation alloc] initWithTarget:self
-                                               keyPath:kFadeOutValueKeyPath];
-      [fadeOutAnimation_ setDuration:kCloseAnimationDuration];
-      [fadeOutAnimation_ setFrameRate:kFramesPerSecond];
-      [fadeOutAnimation_ setDelegate:self];
-      [fadeOutAnimation_ startAnimation];
-    } else {
-      // -stopAnimation will call the animationDidStop: delegate method
-      // which will clean up the animation.
-      [fadeOutAnimation_ stopAnimation];
-    }
+- (void)mouseExited:(NSEvent*)event {
+  previousState_ = self.hoverState;
+  [super mouseExited:event];
+
+  // Only animate the HoverStateNone case.
+  if (self.hoverState == kHoverStateNone) {
+    DCHECK(fadeOutAnimation_ == nil);
+    fadeOutAnimation_ =
+        [[GTMKeyValueAnimation alloc] initWithTarget:self
+                                             keyPath:kFadeOutValueKeyPath];
+    [fadeOutAnimation_ setDuration:kCloseAnimationDuration];
+    [fadeOutAnimation_ setFrameRate:kFramesPerSecond];
+    [fadeOutAnimation_ setDelegate:self];
+    [fadeOutAnimation_ startAnimation];
+  } else {
+    // -stopAnimation will call the animationDidStop: delegate method
+    // which will clean up the animation.
+    [fadeOutAnimation_ stopAnimation];
   }
 }
 
 - (void)commonInit {
   // Set accessibility description.
   NSCell* cell = [self cell];
   [cell accessibilitySetOverrideValue:gDescription
                          forAttribute:NSAccessibilityDescriptionAttribute];
 
   // Add a tooltip. Using 'owner:self' means that
@@ skipping 38 matching lines @@
       break;
     case kHoverStateMouseDown:
       imageID = IDR_CLOSE_DIALOG_P;
       break;
   }
   ui::ResourceBundle& bundle = ui::ResourceBundle::GetSharedInstance();
   return bundle.GetNativeImageNamed(imageID).ToNSImage();
 }
 
 @end