Add notification mechanism when BrowserActionButton's icon has been updated.

ui/views/controls/menu/menu_item_view.cc

Index: ui/views/controls/menu/menu_item_view.cc
diff --git a/ui/views/controls/menu/menu_item_view.cc b/ui/views/controls/menu/menu_item_view.cc
index 15e7db39e64f632c32e0b4c4dd29f646515b5a0f..23e8de207640f2155b06310920d1b7329c3cee32 100644
--- a/ui/views/controls/menu/menu_item_view.cc
+++ b/ui/views/controls/menu/menu_item_view.cc
@@ -107,7 +107,8 @@ MenuItemView::MenuItemView(MenuDelegate* delegate)
       right_icon_margin_(0),
       requested_menu_position_(POSITION_BEST_FIT),
       actual_menu_position_(requested_menu_position_),
-      use_right_margin_(true) {
+      use_right_margin_(true),
+      lifecycle_observer_(NULL) {
   // NOTE: don't check the delegate for NULL, UpdateMenuPartSizes() supplies a
   // NULL delegate.
   Init(NULL, 0, SUBMENU, delegate);
@@ -587,6 +588,8 @@ MenuItemView::MenuItemView(MenuItemView* parent,
 MenuItemView::~MenuItemView() {
   delete submenu_;
   STLDeleteElements(&removed_items_);
+  if (lifecycle_observer_)
+    lifecycle_observer_->OnDeleted(this);
 }
 
 const char* MenuItemView::GetClassName() const {