It is time.

ui/aura/client/visibility_client.cc

Index: ui/aura/client/visibility_client.cc
diff --git a/ui/aura/client/visibility_client.cc b/ui/aura/client/visibility_client.cc
deleted file mode 100644
index 853c034951f72e795b69581dc5d9cb51329d71cb..0000000000000000000000000000000000000000
--- a/ui/aura/client/visibility_client.cc
+++ /dev/null
@@ -1,35 +0,0 @@
-// Copyright (c) 2012 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.
-
-#include "ui/aura/client/visibility_client.h"
-
-#include "ui/aura/window_event_dispatcher.h"
-#include "ui/aura/window_property.h"
-
-DECLARE_WINDOW_PROPERTY_TYPE(aura::client::VisibilityClient*)
-
-namespace aura {
-namespace client {
-
-// A property key to store a client that handles window visibility changes.
-DEFINE_LOCAL_WINDOW_PROPERTY_KEY(
-    VisibilityClient*, kWindowVisibilityClientKey, NULL);
-
-
-void SetVisibilityClient(Window* window, VisibilityClient* client) {
-  window->SetProperty(kWindowVisibilityClientKey, client);
-}
-
-VisibilityClient* GetVisibilityClient(Window* window) {
-  VisibilityClient* visibility_client = NULL;
-  aura::Window* current = window;
-  do {
-    visibility_client = current->GetProperty(kWindowVisibilityClientKey);
-    current = current->parent();
-  } while (current && !visibility_client);
-  return visibility_client;
-}
-
-}  // namespace client
-}  // namespace aura