Menu for the OSX app launcher.

ui/base/cocoa/controls/hover_image_menu_button.mm

+// Copyright 2013 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 "ui/base/cocoa/controls/hover_image_menu_button.h"
+
+#include "base/mac/foundation_util.h"
+#import "ui/base/cocoa/controls/hover_image_menu_button_cell.h"
+
+@implementation HoverImageMenuButton
+
++ (Class)cellClass {
+  return [HoverImageMenuButtonCell class];
+}
+
+- (id)initWithFrame:(NSRect)frameRect
+          pullsDown:(BOOL)flag {
+  if ((self = [super initWithFrame:frameRect
+                         pullsDown:flag])) {
+    trackingArea_.reset(
+        [[CrTrackingArea alloc] initWithRect:NSZeroRect
+                                     options:NSTrackingInVisibleRect |
+                                             NSTrackingMouseEnteredAndExited |
+                                             NSTrackingActiveInKeyWindow
+                                       owner:self
+                                    userInfo:nil]);
+    [self addTrackingArea:trackingArea_.get()];
+  }
+  return self;
+}
+
+- (HoverImageMenuButtonCell*)hoverImageMenuButtonCell {
+  return base::mac::ObjCCastStrict<HoverImageMenuButtonCell>([self cell]);
+}
+
+- (void)mouseEntered:(NSEvent*)theEvent {
+  [[self cell] setHovered:YES];
+}
+
+- (void)mouseExited:(NSEvent*)theEvent {
+  [[self cell] setHovered:NO];
+}
+
+@end