Reland sticky regexps https://codereview.chromium.org/567313003/

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index 855080c34869ea5b69d800df9f8f34ec626733aa..af4acc39f37cc980ea2d1c5ca47471def93ae948 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -203,6 +203,7 @@ class Genesis BASE_EMBEDDED {
   // New context initialization.  Used for creating a context from scratch.
   void InitializeGlobal(Handle<GlobalObject> global_object,
                         Handle<JSFunction> empty_function);
+  void InitializeExperimentalGlobal();
   // Installs the contents of the native .js files on the global objects.
   // Used for creating a context from scratch.
   void InstallNativeFunctions();
@@ -1351,6 +1352,20 @@ void Genesis::InstallTypedArray(
 }
 
 
+void Genesis::InitializeExperimentalGlobal() {
+  // TODO(erikcorry): Move this into Genesis::InitializeGlobal once we no
+  // longer need to live behind a flag.
+  Handle<JSObject> builtins(native_context()->builtins());
+
+  Handle<HeapObject> flag(
+      FLAG_harmony_regexps ? heap()->true_value() : heap()->false_value());
+  PropertyAttributes attributes =
+      static_cast<PropertyAttributes>(DONT_DELETE | READ_ONLY);
+  Runtime::DefineObjectProperty(builtins, factory()->harmony_regexps_string(),
+                                flag, attributes).Assert();
+}
+
+
 bool Genesis::CompileBuiltin(Isolate* isolate, int index) {
   Vector<const char> name = Natives::GetScriptName(index);
   Handle<String> source_code =
@@ -2651,6 +2666,7 @@ Genesis::Genesis(Isolate* isolate,
 
   // Install experimental natives.
   if (!InstallExperimentalNatives()) return;
+  InitializeExperimentalGlobal();
 
   // We can't (de-)serialize typed arrays currently, but we are lucky: The state
   // of the random number generator needs no initialization during snapshot