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"
+
+@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()];
+
+    // Item 0 is the button label, which is not used.
+    [[self menu] addItemWithTitle:[NSString string]

[tapted, 2013/06/03 12:49:18]

note: I've removed this from HoverImageMenuButton. It doesn't work with the
fixed setDelegate, and it will play nicer with c/b/ui/cocoa/menu_controller.mm
this way too.

+                           action:NULL
+                    keyEquivalent:[NSString string]];
+  }
+  return self;
+}
+
+- (void)mouseEntered:(NSEvent*)theEvent {
+  [[self cell] setHovered:YES];
+  [self setNeedsDisplay:YES];
+}
+
+- (void)mouseExited:(NSEvent*)theEvent {
+  [[self cell] setHovered:NO];
+  [self setNeedsDisplay:YES];
+}
+
+@end