Import Reversed adapter from Chromium and use it in v8.

src/base/macros.h

Index: src/base/macros.h
diff --git a/src/base/macros.h b/src/base/macros.h
index ce75f8bed757145f2c4687431f1dda023f43aec9..49ca386aabd7c788e59d2ab4c88277be55b70eb1 100644
--- a/src/base/macros.h
+++ b/src/base/macros.h
@@ -228,6 +228,10 @@ V8_INLINE Dest bit_cast(Source const& source) {
 }
 
 
+// Put this in the private: declarations for a class to be unassignable.
+#define DISALLOW_ASSIGN(TypeName) void operator=(const TypeName&)
+
+
 // A macro to disallow the evil copy constructor and operator= functions
 // This should be used in the private: declarations for a class
 #define DISALLOW_COPY_AND_ASSIGN(TypeName)  \