Notify launcher page with onTransitionChanged event

ui/app_list/views/contents_view.cc

Index: ui/app_list/views/contents_view.cc
diff --git a/ui/app_list/views/contents_view.cc b/ui/app_list/views/contents_view.cc
index 1bc3e5b1bd44de5b9a9f4b6dbc601f6382a67851..478003a22fecd61b77208dbb37da334d4e9eb315 100644
--- a/ui/app_list/views/contents_view.cc
+++ b/ui/app_list/views/contents_view.cc
@@ -56,7 +56,14 @@ void ContentsView::Init(AppListModel* model,
              custom_page_views.begin();
          it != custom_page_views.end();
          ++it) {
-      AddLauncherPage(*it, IDR_APP_LIST_NOTIFICATIONS_ICON);
+      // Only the first launcher page should be the custom launcher page state.
+      if (it == custom_page_views.begin()) {
+        AddLauncherPage(*it,
+                        IDR_APP_LIST_NOTIFICATIONS_ICON,
+                        AppListModel::STATE_CUSTOM_LAUNCHER_PAGE);
+      } else {
+        AddLauncherPage(*it, IDR_APP_LIST_NOTIFICATIONS_ICON);
+      }
     }
 
     start_page_view_ = new StartPageView(app_list_main_view_, view_delegate);