Revert of Use a C++11 feature in a single file, to discover if this works everywhere.

base/compiler_specific.h

 // 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.
 
 #ifndef BASE_COMPILER_SPECIFIC_H_
 #define BASE_COMPILER_SPECIFIC_H_
 
 #include "build/build_config.h"
 
 #if defined(COMPILER_MSVC)
@@ skipping 119 matching lines @@
 #if defined(COMPILER_MSVC)
 #define ALIGNOF(type) (sizeof(type) - sizeof(type) + __alignof(type))
 #elif defined(COMPILER_GCC)
 #define ALIGNOF(type) __alignof__(type)
 #endif
 
 // Annotate a virtual method indicating it must be overriding a virtual
 // method in the parent class.
 // Use like:
 //   virtual void foo() OVERRIDE;
+#if defined(__clang__) || defined(COMPILER_MSVC)
 #define OVERRIDE override
+#elif defined(COMPILER_GCC) && __cplusplus >= 201103 && \
+      (__GNUC__ * 10000 + __GNUC_MINOR__ * 100) >= 40700
+// GCC 4.7 supports explicit virtual overrides when C++11 support is enabled.
+#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:
 //   virtual void foo() FINAL;
 //   class B FINAL : public A {};
+#if defined(__clang__) || defined(COMPILER_MSVC)
 #define FINAL final
+#elif defined(COMPILER_GCC) && __cplusplus >= 201103 && \
+      (__GNUC__ * 10000 + __GNUC_MINOR__ * 100) >= 40700
+// GCC 4.7 supports explicit virtual overrides when C++11 support is enabled.
+#define FINAL final
+#else
+#define FINAL
+#endif
 
 // Annotate a function indicating the caller must examine the return value.
 // Use like:
 //   int foo() WARN_UNUSED_RESULT;
 // To explicitly ignore a result, see |ignore_result()| in <base/basictypes.h>.
 #if defined(COMPILER_GCC)
 #define WARN_UNUSED_RESULT __attribute__((warn_unused_result))
 #else
 #define WARN_UNUSED_RESULT
 #endif
@@ skipping 41 matching lines @@
 // Macro for hinting that an expression is likely to be false.
 #if !defined(UNLIKELY)
 #if defined(COMPILER_GCC)
 #define UNLIKELY(x) __builtin_expect(!!(x), 0)
 #else
 #define UNLIKELY(x) (x)
 #endif  // defined(COMPILER_GCC)
 #endif  // !defined(UNLIKELY)
 
 #endif  // BASE_COMPILER_SPECIFIC_H_