Add a --harmony-object-observe runtime flag (on by default)

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index 03f888b13ca8e01393bbe89ebaf7d1d7d166ae7e..c46cc2e525455951a6f7f0613e0e3153eb113b33 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -1851,6 +1851,7 @@ EMPTY_NATIVE_FUNCTIONS_FOR_FEATURE(harmony_reflect)
 EMPTY_NATIVE_FUNCTIONS_FOR_FEATURE(harmony_spreadcalls)
 EMPTY_NATIVE_FUNCTIONS_FOR_FEATURE(harmony_destructuring)
 EMPTY_NATIVE_FUNCTIONS_FOR_FEATURE(harmony_object)
+EMPTY_NATIVE_FUNCTIONS_FOR_FEATURE(harmony_object_observe)
 EMPTY_NATIVE_FUNCTIONS_FOR_FEATURE(harmony_spread_arrays)
 EMPTY_NATIVE_FUNCTIONS_FOR_FEATURE(harmony_sharedarraybuffer)
 EMPTY_NATIVE_FUNCTIONS_FOR_FEATURE(harmony_atomics)
@@ -1886,6 +1887,7 @@ EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_rest_parameters)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_spreadcalls)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_destructuring)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_object)
+EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_object_observe)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_spread_arrays)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_atomics)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_new_target)
@@ -2573,6 +2575,8 @@ bool Genesis::InstallExperimentalNatives() {
   static const char* harmony_destructuring_natives[] = {nullptr};
   static const char* harmony_object_natives[] = {"native harmony-object.js",
                                                  NULL};
+  static const char* harmony_object_observe_natives[] = {
+      "native harmony-object-observe.js", nullptr};
   static const char* harmony_spread_arrays_natives[] = {nullptr};
   static const char* harmony_sharedarraybuffer_natives[] = {
       "native harmony-sharedarraybuffer.js", NULL};