Revert "Don't use OwnPrototypeChainLength in GetOwnPropertyNames"

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index 4c8723cdd44f3b07b3e91935e232eb7fc3e36f57..23360fefc41a2123e5ed1dde78529eafdf45b5ff 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -5753,6 +5753,19 @@ RUNTIME_FUNCTION(Runtime_GetPropertyNamesFast) {
 }
 
 
+// Find the length of the prototype chain that is to be handled as one. If a
+// prototype object is hidden it is to be viewed as part of the the object it
+// is prototype for.
+static int OwnPrototypeChainLength(JSObject* obj) {
+  int count = 1;
+  for (PrototypeIterator iter(obj->GetIsolate(), obj);
+       !iter.IsAtEnd(PrototypeIterator::END_AT_NON_HIDDEN); iter.Advance()) {
+    count++;
+  }
+  return count;
+}
+
+
 // Return the names of the own named properties.
 // args[0]: object
 // args[1]: PropertyAttributes as int
@@ -5766,12 +5779,30 @@ RUNTIME_FUNCTION(Runtime_GetOwnPropertyNames) {
   CONVERT_SMI_ARG_CHECKED(filter_value, 1);
   PropertyAttributes filter = static_cast<PropertyAttributes>(filter_value);
 
+  // Skip the global proxy as it has no properties and always delegates to the
+  // real global object.
+  if (obj->IsJSGlobalProxy()) {
+    // Only collect names if access is permitted.
+    if (obj->IsAccessCheckNeeded() &&
+        !isolate->MayNamedAccess(
+            obj, isolate->factory()->undefined_value(), v8::ACCESS_KEYS)) {
+      isolate->ReportFailedAccessCheck(obj, v8::ACCESS_KEYS);
+      RETURN_FAILURE_IF_SCHEDULED_EXCEPTION(isolate);
+      return *isolate->factory()->NewJSArray(0);
+    }
+    PrototypeIterator iter(isolate, obj);
+    obj = Handle<JSObject>::cast(PrototypeIterator::GetCurrent(iter));
+  }
+
+  // Find the number of objects making up this.
+  int length = OwnPrototypeChainLength(*obj);
+
   // Find the number of own properties for each of the objects.
+  ScopedVector<int> own_property_count(length);
   int total_property_count = 0;
   {
     PrototypeIterator iter(isolate, obj, PrototypeIterator::START_AT_RECEIVER);
-    for (; !iter.IsAtEnd(PrototypeIterator::END_AT_NON_HIDDEN);
-         iter.Advance()) {
+    for (int i = 0; i < length; i++) {
       DCHECK(!iter.IsAtEnd());
       Handle<JSObject> jsproto =
           Handle<JSObject>::cast(PrototypeIterator::GetCurrent(iter));
@@ -5786,7 +5817,9 @@ RUNTIME_FUNCTION(Runtime_GetOwnPropertyNames) {
       }
       int n;
       n = jsproto->NumberOfOwnProperties(filter);
+      own_property_count[i] = n;
       total_property_count += n;
+      iter.Advance();
     }
   }
 
@@ -5799,18 +5832,17 @@ RUNTIME_FUNCTION(Runtime_GetOwnPropertyNames) {
   int hidden_strings = 0;
   {
     PrototypeIterator iter(isolate, obj, PrototypeIterator::START_AT_RECEIVER);
-    for (; !iter.IsAtEnd(PrototypeIterator::END_AT_NON_HIDDEN);
-         iter.Advance()) {
+    for (int i = 0; i < length; i++) {
+      DCHECK(!iter.IsAtEnd());
       Handle<JSObject> jsproto =
           Handle<JSObject>::cast(PrototypeIterator::GetCurrent(iter));
-      int own_property_count =
-          jsproto->GetOwnPropertyNames(*names, next_copy_index, filter);
-      if (!jsproto.is_identical_to(obj)) {
+      jsproto->GetOwnPropertyNames(*names, next_copy_index, filter);
+      if (i > 0) {
         // Names from hidden prototypes may already have been added
         // for inherited function template instances. Count the duplicates
         // and stub them out; the final copy pass at the end ignores holes.
-        for (int j = next_copy_index; j < next_copy_index + own_property_count;
-             j++) {
+        for (int j = next_copy_index;
+             j < next_copy_index + own_property_count[i]; j++) {
           Object* name_from_hidden_proto = names->get(j);
           for (int k = 0; k < next_copy_index; k++) {
             if (names->get(k) != isolate->heap()->hidden_string()) {
@@ -5824,12 +5856,13 @@ RUNTIME_FUNCTION(Runtime_GetOwnPropertyNames) {
           }
         }
       }
-      next_copy_index += own_property_count;
+      next_copy_index += own_property_count[i];
 
       // Hidden properties only show up if the filter does not skip strings.
       if ((filter & STRING) == 0 && JSObject::HasHiddenProperties(jsproto)) {
         hidden_strings++;
       }
+      iter.Advance();
     }
   }