Add FINAL to base/compiler_specific.

base/compiler_specific.h

 // Copyright (c) 2011 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.
 
 #ifndef BASE_COMPILER_SPECIFIC_H_
 #define BASE_COMPILER_SPECIFIC_H_
 #pragma once
 
 #include "build/build_config.h"
 
@@ skipping 119 matching lines @@
 #define PRINTF_FORMAT(format_param, dots_param)
 #endif
 
 // WPRINTF_FORMAT is the same, but for wide format strings.
 // This doesn't appear to yet be implemented in any compiler.
 // See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38308 .
 #define WPRINTF_FORMAT(format_param, dots_param)
 // If available, it would look like:
 //   __attribute__((format(wprintf, format_param, dots_param)))
 
+// Annotate a class to indicate that it cannot be subclassed. Use this very
+// sparingly.  The only valid use case is if you have a class with virtual
+// methods but no virtual destructor -- see http://crbug.com/84424
+// Use like:
+//   class B FINAL : public A {};
+#if defined(__clang__)

[Mark Mentovai, 2011/05/31 14:41:05]

Should we have COMPILER_CLANG?

+#define FINAL final

[Mark Mentovai, 2011/05/31 14:41:05]

I’m surprised it’s final and not __final__ or an __attribute__.

+#else
+#define FINAL
+#endif
+
 #endif  // BASE_COMPILER_SPECIFIC_H_