Update app list search box menu when Users changes

ui/app_list/app_list_view_delegate.cc

Index: ui/app_list/app_list_view_delegate.cc
diff --git a/ui/app_list/app_list_view_delegate.cc b/ui/app_list/app_list_view_delegate.cc
index 2156cf5065e9a246ba06b6467068b308987f44ce..c84985b820665df91f6540c73a19d426fa40bedc 100644
--- a/ui/app_list/app_list_view_delegate.cc
+++ b/ui/app_list/app_list_view_delegate.cc
@@ -4,6 +4,8 @@
 
 #include "ui/app_list/app_list_view_delegate.h"
 
+#include "ui/app_list/app_list_view_delegate_observer.h"
+
 namespace app_list {
 
 AppListViewDelegate::User::User() : active(false) {
@@ -12,4 +14,23 @@ AppListViewDelegate::User::User() : active(false) {
 AppListViewDelegate::User::~User() {
 }
 
+const AppListViewDelegate::Users& AppListViewDelegate::GetUsers() const {
+  return users_;
+}
+
+void AppListViewDelegate::AddObserver(AppListViewDelegateObserver* observer) {
+  observers_.AddObserver(observer);
+}
+
+void AppListViewDelegate::RemoveObserver(
+    AppListViewDelegateObserver* observer) {
+  observers_.RemoveObserver(observer);
+}
+
+void AppListViewDelegate::NotifyUsersChanged() {
+  FOR_EACH_OBSERVER(AppListViewDelegateObserver,
+                    observers_,
+                    OnUsersChanged());
+}
+
 }  // app_list