--verify-predictable mode added for ensuring that GC behaves deterministically.

Makefile

 # 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 52 matching lines @@
 # verifyheap=on
 ifeq ($(verifyheap), on)
   GYPFLAGS += -Dv8_enable_verify_heap=1
 endif
 # backtrace=off
 ifeq ($(backtrace), off)
   GYPFLAGS += -Dv8_enable_backtrace=0
 else
   GYPFLAGS += -Dv8_enable_backtrace=1
 endif
+# verifypredictable=on
+ifeq ($(verifypredictable), on)
+  GYPFLAGS += -Dv8_enable_verify_predictable=1
+endif
 # snapshot=off
 ifeq ($(snapshot), off)
   GYPFLAGS += -Dv8_use_snapshot='false'
 endif
 # extrachecks=on/off
 ifeq ($(extrachecks), on)
   GYPFLAGS += -Dv8_enable_extra_checks=1 -Dv8_enable_handle_zapping=1
 endif
 ifeq ($(extrachecks), off)
   GYPFLAGS += -Dv8_enable_extra_checks=0 -Dv8_enable_handle_zapping=0
@@ skipping 383 matching lines @@
         svn checkout --force http://gyp.googlecode.com/svn/trunk build/gyp \
             --revision 1831
         svn checkout --force \
             https://src.chromium.org/chrome/trunk/deps/third_party/icu46 \
             third_party/icu --revision 258359
         ( test -d buildtools || \
           git clone https://chromium.googlesource.com/chromium/buildtools.git; \
           cd buildtools; \
           git fetch origin; \
           git checkout 5d89977ce55240995d1596fe420b818468f5ec37 )