Add flag for printing the time it took to deserialize the snapshot.

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 577 matching lines @@
             "preallocate some memory to build stack traces.")
 DEFINE_bool(randomize_hashes,
             true,
             "randomize hashes to avoid predictable hash collisions "
             "(with snapshots this option cannot override the baked-in seed)")
 DEFINE_int(hash_seed,
            0,
            "Fixed seed to use to hash property keys (0 means random)"
            "(with snapshots this option cannot override the baked-in seed)")
 
+// snapshot-common.cc
+DEFINE_bool(profile_deserialization,
+            false,
+            "Print the time it takes to deserialize the snapshot.")
+
 // v8.cc
 DEFINE_bool(preemption, false,
             "activate a 100ms timer that switches between V8 threads")
 
 // Regexp
 DEFINE_bool(regexp_optimization, true, "generate optimized regexp code")
 
 // Testing flags test/cctest/test-{flags,api,serialization}.cc
 DEFINE_bool(testing_bool_flag, true, "testing_bool_flag")
 DEFINE_maybe_bool(testing_maybe_bool_flag, "testing_maybe_bool_flag")
@@ skipping 244 matching lines @@
 #undef DEFINE_ALIAS_float
 #undef DEFINE_ALIAS_args
 
 #undef FLAG_MODE_DECLARE
 #undef FLAG_MODE_DEFINE
 #undef FLAG_MODE_DEFINE_DEFAULTS
 #undef FLAG_MODE_META
 #undef FLAG_MODE_DEFINE_IMPLICATIONS
 
 #undef COMMA