Move some code from Runtime_GetPrototype into a new Object::GetPrototype.

src/objects.cc

 // Copyright 2013 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/objects.h"
 
 #include <cmath>
 #include <iomanip>
 #include <sstream>
 
@@ skipping 13868 matching lines @@
 
 
 MaybeHandle<Object> JSObject::SetPrototype(Handle<JSObject> object,
                                            Handle<Object> value,
                                            bool from_javascript) {
   Isolate* isolate = object->GetIsolate();
 
   const bool observed = from_javascript && object->map()->is_observed();
   Handle<Object> old_value;
   if (observed) {
-    old_value = Object::GetPrototypeSkipHiddenPrototypes(isolate, object);
+    old_value = Object::GetPrototype(isolate, object);
   }
 
   Handle<Object> result;
   ASSIGN_RETURN_ON_EXCEPTION(
       isolate, result, SetPrototypeUnobserved(object, value, from_javascript),
       Object);
 
   if (observed) {
-    Handle<Object> new_value =
-        Object::GetPrototypeSkipHiddenPrototypes(isolate, object);
+    Handle<Object> new_value = Object::GetPrototype(isolate, object);
     if (!new_value->SameValue(*old_value)) {
       RETURN_ON_EXCEPTION(isolate,
                           JSObject::EnqueueChangeRecord(
                               object, "setPrototype",
                               isolate->factory()->proto_string(), old_value),
                           Object);
     }
   }
 
   return result;
@@ skipping 3903 matching lines @@
   if (cell->value() != *new_value) {
     cell->set_value(*new_value);
     Isolate* isolate = cell->GetIsolate();
     cell->dependent_code()->DeoptimizeDependentCodeGroup(
         isolate, DependentCode::kPropertyCellChangedGroup);
   }
 }
 
 }  // namespace internal
 }  // namespace v8