Re-land: Use map transitions when defining accessor properties.

src/flag-definitions.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 379 matching lines @@
             "Compact code space on full non-incremental collections")
 DEFINE_bool(cleanup_code_caches_at_gc, true,
             "Flush inline caches prior to mark compact collection and "
             "flush code caches in maps during mark compact cycle.")
 DEFINE_int(random_seed, 0,
            "Default seed for initializing random generator "
            "(0, the default, means to use system random).")
 
 // objects.cc
 DEFINE_bool(use_verbose_printer, true, "allows verbose printing")
+DEFINE_bool(fast_accessor_properties, false,
+            "use map transitions for JavaScript accessors")
 
 // parser.cc
 DEFINE_bool(allow_natives_syntax, false, "allow natives syntax")
 
 // simulator-arm.cc and simulator-mips.cc
 DEFINE_bool(trace_sim, false, "Trace simulator execution")
 DEFINE_bool(check_icache, false,
             "Check icache flushes in ARM and MIPS simulator")
 DEFINE_int(stop_sim_at, 0, "Simulator stop after x number of instructions")
 DEFINE_int(sim_stack_alignment, 8,
@@ skipping 246 matching lines @@
 #undef DEFINE_bool
 #undef DEFINE_int
 #undef DEFINE_string
 #undef DEFINE_implication
 
 #undef FLAG_MODE_DECLARE
 #undef FLAG_MODE_DEFINE
 #undef FLAG_MODE_DEFINE_DEFAULTS
 #undef FLAG_MODE_META
 #undef FLAG_MODE_DEFINE_IMPLICATIONS