views/examples: Clean up cpplint warnings.

ui/views/examples/progress_bar_example.cc

Index: ui/views/examples/progress_bar_example.cc
diff --git a/ui/views/examples/progress_bar_example.cc b/ui/views/examples/progress_bar_example.cc
index 3a93bc598dc4047b93ebf5811b0b145714607a42..223074f4c23972a23b150ae15feed529fddbd361 100644
--- a/ui/views/examples/progress_bar_example.cc
+++ b/ui/views/examples/progress_bar_example.cc
@@ -1,9 +1,11 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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/views/examples/progress_bar_example.h"
 
+#include <algorithm>
+
 #include "base/utf_string_conversions.h"
 #include "ui/views/controls/button/text_button.h"
 #include "ui/views/controls/progress_bar.h"