Add FINAL and OVERRIDE macros for C++11 final/override.

src/globals.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 357 matching lines @@
 #endif
 #elif defined(_MSC_VER) && !defined(DEBUG)
 #define INLINE(header) __forceinline header
 #define NO_INLINE(header) header
 #else
 #define INLINE(header) inline header
 #define NO_INLINE(header) header
 #endif
 
 
+// Annotate a virtual method indicating it must be overriding a virtual
+// method in the parent class.
+// Use like:
+//   virtual void bar() OVERRIDE;
+#if __cplusplus >= 201103L

[Sven Panne, 2013/08/19 12:44:48]

Looking at Chrome's base/compiler_specific.h, I think we can use it more often:
MSVC supports this for ages (VS2005 at least) and clang supports it. Checking
the C++ version should be used as a fallback.

+#define OVERRIDE override
+#else
+#define OVERRIDE
+#endif
+
+
+// Annotate a virtual method indicating that subclasses must not override it,
+// or annotate a class to indicate that it cannot be subclassed.
+// Use like:
+//   class B FINAL : public A {};
+//   virtual void bar() FINAL;
+#if __cplusplus >= 201103L

[Sven Panne, 2013/08/19 12:44:48]

Same here: For MSVC we can fall back to 'sealed', clang has it, otherwise check
C++ version.

+#define FINAL final
+#else
+#define FINAL
+#endif
+
+
 #if defined(__GNUC__) && __GNUC__ >= 4
 #define MUST_USE_RESULT __attribute__ ((warn_unused_result))
 #else
 #define MUST_USE_RESULT
 #endif
 
 
 // Define DISABLE_ASAN macros.
 #if defined(__has_feature)
 #if __has_feature(address_sanitizer)
@@ skipping 55 matching lines @@
 // the backend, so both modes are represented by the kStrictMode value.
 enum StrictModeFlag {
   kNonStrictMode,
   kStrictMode
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_GLOBALS_H_