Fix bug in Array.prototype.indexOf/lastIndexOf when called on non-sparse non-arrays.

src/runtime.cc

 // Copyright 2006-2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 7964 matching lines @@
   to->set_map(Map::cast(new_map));
   to->set_elements(new_elements);
   to->set_length(from->length());
   Object* obj = from->ResetElements();
   if (obj->IsFailure()) return obj;
   from->set_length(Smi::FromInt(0));
   return to;
 }
 
 
-// How many elements does this array have?
+// How many elements does this object/array have?
 static Object* Runtime_EstimateNumberOfElements(Arguments args) {
   ASSERT(args.length() == 1);
-  CONVERT_CHECKED(JSArray, array, args[0]);
-  HeapObject* elements = array->elements();
+  CONVERT_CHECKED(JSObject, object, args[0]);
+  HeapObject* elements = object->elements();
   if (elements->IsDictionary()) {
     return Smi::FromInt(NumberDictionary::cast(elements)->NumberOfElements());
+  } else if (object->IsJSArray()) {
+    return JSArray::cast(object)->length();
   } else {
-    return array->length();
+    return Smi::FromInt(FixedArray::cast(elements)->length());
   }
 }
 
 
 static Object* Runtime_SwapElements(Arguments args) {
   HandleScope handle_scope;
 
   ASSERT_EQ(3, args.length());
 
   CONVERT_ARG_CHECKED(JSObject, object, 0);
@@ skipping 2529 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     Counters::gc_last_resort_from_js.Increment();
     Heap::CollectAllGarbage(false);
   }
 }
 
 
 } }  // namespace v8::internal