Add Flags<T> class as a type-safe way of storing OR-combinations of enums.

tools/gyp/v8.gyp

 # 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 1112 matching lines @@
         '../../src/base/atomicops_internals_mac.h',
         '../../src/base/atomicops_internals_mips_gcc.h',
         '../../src/base/atomicops_internals_tsan.h',
         '../../src/base/atomicops_internals_x86_gcc.cc',
         '../../src/base/atomicops_internals_x86_gcc.h',
         '../../src/base/atomicops_internals_x86_msvc.h',
         '../../src/base/bits.h',
         '../../src/base/build_config.h',
         '../../src/base/cpu.cc',
         '../../src/base/cpu.h',
+        '../../src/base/flags.h',
         '../../src/base/lazy-instance.h',
         '../../src/base/logging.cc',
         '../../src/base/logging.h',
         '../../src/base/macros.h',
         '../../src/base/once.cc',
         '../../src/base/once.h',
         '../../src/base/platform/elapsed-timer.h',
         '../../src/base/platform/time.cc',
         '../../src/base/platform/time.h',
         '../../src/base/platform/condition-variable.cc',
@@ skipping 430 matching lines @@
         }],
         ['v8_compress_startup_data=="bz2"', {
           'libraries': [
             '-lbz2',
           ]
         }],
       ],
     },
   ],
 }