Fix incorrect guards in base/.

base/clipboard_util.h

 // Copyright (c) 2006-2008 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.
 //
 // Some helper functions for working with the clipboard and IDataObjects.
 
+#ifndef BASE_CLIPBOARD_UTIL_H_
+#define BASE_CLIPBOARD_UTIL_H_
+
 #include <shlobj.h>
 #include <string>
 #include <vector>
 
 class ClipboardUtil {
  public:
   /////////////////////////////////////////////////////////////////////////////
   // Clipboard formats.
   static FORMATETC* GetUrlFormat();
   static FORMATETC* GetUrlWFormat();
@@ skipping 32 matching lines @@
                               std::wstring* filename,
                               std::string* file_contents);
 
   // A helper method for converting between MS CF_HTML format and plain
   // text/html.
   static std::string HtmlToCFHtml(const std::string& html,
                                   const std::string& base_url);
   static void CFHtmlToHtml(const std::string& cf_html, std::string* html,
                            std::string* base_url);
 };
+
+#endif  // BASE_CLIPBOARD_UTIL_H_