Simplify GetEnumPropertyKeys and avoid trimming fixed arrays in large object space.

src/handles.cc

Index: src/handles.cc
diff --git a/src/handles.cc b/src/handles.cc
index 899f9bfb5c8d0d15c1e5fb578670b09848c09835..398a68265cdf1c65d2b98a4d459ab972bbe34cef 100644
--- a/src/handles.cc
+++ b/src/handles.cc
@@ -712,35 +712,12 @@ Handle<FixedArray> GetEnumPropertyKeys(Handle<JSObject> object,
     return ReduceFixedArrayTo(storage, enum_size);
   } else {
     Handle<NameDictionary> dictionary(object->property_dictionary());
-
-    int length = dictionary->NumberOfElements();
+    int length = dictionary->NumberOfEnumElements();
     if (length == 0) {
       return Handle<FixedArray>(isolate->heap()->empty_fixed_array());
     }
-
-    // The enumeration array is generated by allocating an array big enough to
-    // hold all properties that have been seen, whether they are are deleted or
-    // not. Subsequently all visible properties are added to the array. If some
-    // properties were not visible, the array is trimmed so it only contains
-    // visible properties. This improves over adding elements and sorting by
-    // index by having linear complexity rather than n*log(n).
-
-    // By comparing the monotonous NextEnumerationIndex to the NumberOfElements,
-    // we can predict the number of holes in the final array. If there will be
-    // more than 50% holes, regenerate the enumeration indices to reduce the
-    // number of holes to a minimum. This avoids allocating a large array if
-    // many properties were added but subsequently deleted.
-    int next_enumeration = dictionary->NextEnumerationIndex();
-    if (!object->IsGlobalObject() && next_enumeration > (length * 3) / 2) {
-      NameDictionary::DoGenerateNewEnumerationIndices(dictionary);
-      next_enumeration = dictionary->NextEnumerationIndex();
-    }
-
-    Handle<FixedArray> storage =
-        isolate->factory()->NewFixedArray(next_enumeration);
-
-    storage = Handle<FixedArray>(dictionary->CopyEnumKeysTo(*storage));
-    ASSERT(storage->length() == object->NumberOfLocalProperties(DONT_SHOW));
+    Handle<FixedArray> storage = isolate->factory()->NewFixedArray(length);
+    dictionary->CopyEnumKeysTo(*storage);
     return storage;
   }
 }