[prototype user tracking] Don't skip JSGlobalProxies

src/factory.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/factory.h"
 
 #include "src/allocation-site-scopes.h"
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
 #include "src/conversions.h"
@@ skipping 2016 matching lines @@
   CALL_HEAP_FUNCTION(
       isolate(), isolate()->heap()->AllocateJSObjectFromMap(*map, NOT_TENURED),
       JSGlobalProxy);
 }
 
 
 void Factory::ReinitializeJSGlobalProxy(Handle<JSGlobalProxy> object,
                                         Handle<JSFunction> constructor) {
   DCHECK(constructor->has_initial_map());
   Handle<Map> map(constructor->initial_map(), isolate());
+  Handle<Map> old_map(object->map(), isolate());
 
   // The proxy's hash should be retained across reinitialization.
   Handle<Object> hash(object->hash(), isolate());
 
+  JSObject::InvalidatePrototypeChains(*old_map);
+  if (old_map->is_prototype_map()) {
+    map = Map::Copy(map, "CopyAsPrototypeForJSGlobalProxy");
+    map->set_is_prototype_map(true);
+  }
+  JSObject::UpdatePrototypeUserRegistration(old_map, map, isolate());
+
   // Check that the already allocated object has the same size and type as
   // objects allocated using the constructor.
-  DCHECK(map->instance_size() == object->map()->instance_size());
-  DCHECK(map->instance_type() == object->map()->instance_type());
+  DCHECK(map->instance_size() == old_map->instance_size());
+  DCHECK(map->instance_type() == old_map->instance_type());
 
   // Allocate the backing storage for the properties.
   Handle<FixedArray> properties = empty_fixed_array();
 
   // In order to keep heap in consistent state there must be no allocations
   // before object re-initialization is finished.
   DisallowHeapAllocation no_allocation;
 
   // Reset the map for the object.
   object->synchronized_set_map(*map);
@@ skipping 321 matching lines @@
 }
 
 
 Handle<Object> Factory::ToBoolean(bool value) {
   return value ? true_value() : false_value();
 }
 
 
 }  // namespace internal
 }  // namespace v8