[es6] Partially implement Reflect.getOwnPropertyDescriptor.

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 6558 matching lines @@
     isolate->Throw(*isolate->factory()->NewTypeError(
         MessageTemplate::kStrictDeleteProperty,
         isolate->factory()->NewNumberFromUint(actual_new_len - 1), a));
   }
   return success;
 }
 
 
 // static
 bool JSReceiver::GetOwnPropertyDescriptor(Isolate* isolate,
-                                          Handle<JSObject> object,
+                                          Handle<JSReceiver> object,
                                           Handle<Object> key,
                                           PropertyDescriptor* desc) {
   bool success = false;
   DCHECK(key->IsName() || key->IsNumber());  // |key| is a PropertyKey...
   LookupIterator it = LookupIterator::PropertyOrElement(
       isolate, object, key, &success, LookupIterator::HIDDEN);
   DCHECK(success);  // ...so creating a LookupIterator can't fail.
   return GetOwnPropertyDescriptor(&it, desc);
 }
 
@@ skipping 11282 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