Introduce a handle zapping setting, and enable it by default for release and debug

build/common.gypi

 # 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 472 matching lines @@
         'cflags': [ '-I/usr/local/include' ],
       }],
       ['OS=="netbsd"', {
         'cflags': [ '-I/usr/pkg/include' ],
       }],
     ],  # conditions
     'configurations': {
       'Debug': {
         'variables': {
           'v8_enable_extra_checks%': 1,
+          'v8_enable_handle_zapping%': 1,
         },
         'defines': [
           'DEBUG',
           'ENABLE_DISASSEMBLER',
           'V8_ENABLE_CHECKS',
           'OBJECT_PRINT',
           'VERIFY_HEAP',
         ],
         'msvs_settings': {
           'VCCLCompilerTool': {
             'Optimization': '0',
 
             'conditions': [
               ['OS=="win" and component=="shared_library"', {
                 'RuntimeLibrary': '3',  # /MDd
               }, {
                 'RuntimeLibrary': '1',  # /MTd
               }],
             ],
           },
           'VCLinkerTool': {
             'LinkIncremental': '2',
           },
         },
         'conditions': [
           ['v8_enable_extra_checks==1', {
             'defines': ['ENABLE_EXTRA_CHECKS',],
           }],
+          ['v8_enable_handle_zapping==1', {
+            'defines': ['ENABLE_HANDLE_ZAPPING',],
+          }],
           ['OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="netbsd"', {
             'cflags': [ '-Wall', '<(werror)', '-W', '-Wno-unused-parameter',
                         '-Wnon-virtual-dtor', '-Woverloaded-virtual' ],
           }],
           ['OS=="linux" and v8_enable_backtrace==1', {
             # Support for backtrace_symbols.
             'ldflags': [ '-rdynamic' ],
           }],
           ['OS=="android"', {
             'variables': {
@@ skipping 12 matching lines @@
           ['OS=="mac"', {
             'xcode_settings': {
               'GCC_OPTIMIZATION_LEVEL': '0',  # -O0
             },
           }],
         ],
       },  # Debug
       'Release': {
         'variables': {
           'v8_enable_extra_checks%': 0,
+          'v8_enable_handle_zapping%': 1,
         },
         'conditions': [
           ['v8_enable_extra_checks==1', {
             'defines': ['ENABLE_EXTRA_CHECKS',],
           }],
+          ['v8_enable_handle_zapping==1', {
+            'defines': ['ENABLE_HANDLE_ZAPPING',],
+          }],
           ['OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="netbsd"', {
             'cflags!': [
               '-O2',
               '-Os',
             ],
             'cflags': [
               '-fdata-sections',
               '-ffunction-sections',
               '-O3',
             ],
@@ skipping 61 matching lines @@
                 'OptimizeReferences': '2',
                 'EnableCOMDATFolding': '2',
               },
             },
           }],  # OS=="win"
         ],  # conditions
       },  # Release
     },  # configurations
   },  # target_defaults
 }