Ensure slow properties for simple {__proto__:null} literals.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 7faa146bb155d7d84f4288b05f5831a2977a17ea..edaae536ec70e7ca899a06ce4e13796b2b6c7fd9 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -2834,6 +2834,10 @@ class FixedArray: public FixedArrayBase {
   static const int kMaxSize = 128 * MB * kPointerSize;
   // Maximally allowed length of a FixedArray.
   static const int kMaxLength = (kMaxSize - kHeaderSize) / kPointerSize;
+  // Maximally allowed length for regular (non large object space) object.
+  STATIC_ASSERT(kMaxRegularHeapObjectSize < kMaxSize);
+  static const int kMaxRegularLength =
+      (kMaxRegularHeapObjectSize - kHeaderSize) / kPointerSize;
 
   // Dispatched behavior.
   DECLARE_PRINTER(FixedArray)
@@ -4835,6 +4839,9 @@ class Map: public HeapObject {
   static Handle<Map> CopyInitialMap(Handle<Map> map, int instance_size,
                                     int in_object_properties,
                                     int unused_property_fields);
+  static Handle<Map> CopyInitialMapNormalized(
+      Handle<Map> map,
+      PropertyNormalizationMode mode = CLEAR_INOBJECT_PROPERTIES);
   static Handle<Map> CopyDropDescriptors(Handle<Map> map);
   static Handle<Map> CopyInsertDescriptor(Handle<Map> map,
                                           Descriptor* descriptor,