Split extra checks into extra checks and handle zapping

build/features.gypi

Index: build/features.gypi
diff --git a/build/features.gypi b/build/features.gypi
index 5343284dbc987958368807f65a797af134d6a2cf..8ef58a9d4677854247654ea817d0101a049cc398 100644
--- a/build/features.gypi
+++ b/build/features.gypi
@@ -89,21 +89,29 @@
       'Debug': {
         'variables': {
           'v8_enable_extra_checks%': 1,
+          'v8_enable_handle_zapping%': 1,
         },
         'conditions': [
           ['v8_enable_extra_checks==1', {
             'defines': ['ENABLE_EXTRA_CHECKS',],
           }],
+          ['v8_enable_handle_zapping==1', {
+            'defines': ['ENABLE_HANDLE_ZAPPING',],
+          }],
         ],
       },  # Debug
       'Release': {
         'variables': {
           'v8_enable_extra_checks%': 0,
+          'v8_enable_handle_zapping%': 0,
         },
         'conditions': [
           ['v8_enable_extra_checks==1', {
             'defines': ['ENABLE_EXTRA_CHECKS',],
           }],
+          ['v8_enable_handle_zapping==1', {
+            'defines': ['ENABLE_HANDLE_ZAPPING',],
+          }],
         ],  # conditions
       },  # Release
     },  # configurations