Cleanup: Fix base header include guards.

base/base_paths_win.h

Index: base/base_paths_win.h
diff --git a/base/base_paths_win.h b/base/base_paths_win.h
index 4ab6af1672061723e0be83f7c367cfb21092642a..9ac9e45e0a778d6403a362dc285ffd15d7bb92c1 100644
--- a/base/base_paths_win.h
+++ b/base/base_paths_win.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef BASE_BASE_PATHS_WIN_H__
-#define BASE_BASE_PATHS_WIN_H__
+#ifndef BASE_BASE_PATHS_WIN_H_
+#define BASE_BASE_PATHS_WIN_H_
 
 // This file declares windows-specific path keys for the base module.
 // These can be used with the PathService to access various special
@@ -51,4 +51,4 @@ enum {
 
 }  // namespace base
 
-#endif  // BASE_BASE_PATHS_WIN_H__
+#endif  // BASE_BASE_PATHS_WIN_H_