Introduce a PrototypeIterator template and use it all over the place

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index 89052139dfb598e9f2e3fc46b1998a7746f0ecbf..61381a0f946ab71282a93a5749c6c6a0ce64ccb3 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -1001,10 +1001,10 @@ bool Isolate::IsErrorObject(Handle<Object> obj) {
       js_builtins_object(), error_key).ToHandleChecked();
 
   DisallowHeapAllocation no_gc;
-  for (Object* prototype = *obj; !prototype->IsNull();
-       prototype = prototype->GetPrototype(this)) {
-    if (!prototype->IsJSObject()) return false;
-    if (JSObject::cast(prototype)->map()->constructor() ==
+  for (PrototypeIterator<STORE_AS_POINTER, TYPE_BASED_WALK, END_AT_NULL_VALUE>
+           iter(this, *obj); !iter.IsAtEnd(); iter.Advance()) {
+    if (!iter.GetCurrent()->IsJSObject()) return false;
+    if (JSObject::cast(iter.GetCurrent())->map()->constructor() ==
         *error_constructor) {
       return true;
     }
@@ -2183,13 +2183,13 @@ bool Isolate::IsFastArrayConstructorPrototypeChainIntact() {
 
   // Check that the object prototype hasn't been altered WRT empty elements.
   JSObject* initial_object_proto = JSObject::cast(*initial_object_prototype());
-  Object* root_array_map_proto = initial_array_proto->GetPrototype();
+  Object* root_array_map_proto = SAFE_GET_PROTOTYPE_FAST(initial_array_proto);
   if (root_array_map_proto != initial_object_proto) return false;
   if (initial_object_proto->elements() != heap()->empty_fixed_array()) {
     return false;
   }
 
-  return initial_object_proto->GetPrototype()->IsNull();
+  return SAFE_GET_PROTOTYPE_FAST(initial_object_proto)->IsNull();
 }