Correctly escape RegExp source.

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index 02af9d2fbc1f62cc86717504991ad3c5c08a3811..7ba90200fa6a375930783444bd0138534678713e 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -1044,11 +1044,10 @@ void Genesis::InitializeGlobal(Handle<GlobalObject> global_object,
 
     {
       // ECMA-262, section 15.10.7.1.
-      FieldDescriptor field(factory->source_string(),
-                            JSRegExp::kSourceFieldIndex,
-                            final,
-                            Representation::Tagged());
-      initial_map->AppendDescriptor(&field);
+      Handle<AccessorInfo> regexp_source(
+          Accessors::RegExpSourceInfo(isolate, final));
+      CallbacksDescriptor d(factory->source_string(), regexp_source, final);
+      initial_map->AppendDescriptor(&d);
     }
     {
       // ECMA-262, section 15.10.7.2.
@@ -1085,18 +1084,17 @@ void Genesis::InitializeGlobal(Handle<GlobalObject> global_object,
       initial_map->AppendDescriptor(&field);
     }
 
-    initial_map->set_inobject_properties(5);
-    initial_map->set_pre_allocated_property_fields(5);
+    static const int num_fields = JSRegExp::kInObjectFieldCount;
+    initial_map->set_inobject_properties(num_fields);
+    initial_map->set_pre_allocated_property_fields(num_fields);
     initial_map->set_unused_property_fields(0);
-    initial_map->set_instance_size(
-        initial_map->instance_size() + 5 * kPointerSize);
+    initial_map->set_instance_size(initial_map->instance_size() +
+                                   num_fields * kPointerSize);
 
     // RegExp prototype object is itself a RegExp.
     Handle<Map> proto_map = Map::Copy(initial_map, "RegExpPrototype");
     proto_map->set_prototype(native_context()->initial_object_prototype());
     Handle<JSObject> proto = factory->NewJSObjectFromMap(proto_map);
-    proto->InObjectPropertyAtPut(JSRegExp::kSourceFieldIndex,
-                                 heap->query_colon_string());
     proto->InObjectPropertyAtPut(JSRegExp::kGlobalFieldIndex,
                                  heap->false_value());
     proto->InObjectPropertyAtPut(JSRegExp::kIgnoreCaseFieldIndex,