[Mac] App Menu Animated Icon

chrome/browser/ui/cocoa/menu_button.mm

 // Copyright (c) 2011 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/menu_button.h"
 
 #include "base/logging.h"
 #import "chrome/browser/ui/cocoa/clickhold_button_cell.h"
 #import "chrome/browser/ui/cocoa/toolbar/toolbar_controller.h"
 #include "ui/base/material_design/material_design_controller.h"
@@ skipping 76 matching lines @@
 
 - (void)setOpenMenuOnRightClick:(BOOL)enabled {
   openMenuOnRightClick_ = enabled;
   [self configureCell];
 }
 
 - (NSRect)menuRect {
   return [self bounds];
 }
 
+- (void)willShowMenu {
+  // Subclasses should implement this, but it's not necessary.
+}
+
 @end  // @implementation MenuButton
 
 @implementation MenuButton (Private)
 
 // Synchronize the state of this class with its ClickHoldButtonCell.
 - (void)configureCell {
   ClickHoldButtonCell* cell = [self cell];
   DCHECK([cell isKindOfClass:[ClickHoldButtonCell class]]);
 
   if (![self attachedMenu]) {
@@ skipping 65 matching lines @@
   // the menu correctly even when we're at the edge of the screen (including
   // "dragging upwards" when the button is close to the bottom of the screen).
   // A |scoped_nsobject| local variable cannot be used here because
   // Accessibility on 10.5 grabs the NSPopUpButtonCell without retaining it, and
   // uses it later. (This is fixed in 10.6.)
   if (!popUpCell_.get()) {
     popUpCell_.reset([[NSPopUpButtonCell alloc] initTextCell:@""
                                                    pullsDown:YES]);
   }
   DCHECK(popUpCell_.get());
+  [self willShowMenu];
   [popUpCell_ setMenu:[self attachedMenu]];
   [popUpCell_ selectItem:nil];
   [popUpCell_ attachPopUpWithFrame:frame inView:self];
   [popUpCell_ performClickWithFrame:frame inView:self];
 
   // Once the menu is dismissed send a mouseExited event if necessary. If the
   // menu action caused the super view to resize then we won't automatically
   // get a mouseExited event so we need to do this manually.
   // See http://crbug.com/82456
   if (![self cr_isMouseInView]) {
@@ skipping 11 matching lines @@
 }
 
 // Called when the button is clicked and dragged/held.
 - (void)dragShowMenu:(id)sender {
   // We shouldn't get here unless the menu is enabled.
   DCHECK([self attachedMenu]);
   [self showMenu:YES];
 }
 
 @end  // @implementation MenuButton (Private)