Create read only handles for empty_array and sentinel objects

lib/isolate.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/assert.h"
 #include "vm/bootstrap_natives.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_entry.h"
@@ skipping 355 matching lines @@
     result = state->ResolveFunction();
     delete state;
     state = NULL;
     if (result.IsError()) {
       StoreError(isolate, result);
       return false;
     }
     ASSERT(result.IsFunction());
     Function& func = Function::Handle(isolate);
     func ^= result.raw();
-    const Array& args = Array::Handle(Object::empty_array());
-    result = DartEntry::InvokeStatic(func, args);
+    result = DartEntry::InvokeStatic(func, Object::empty_array());
     if (result.IsError()) {
       StoreError(isolate, result);
       return false;
     }
   }
   return true;
 }
 
 
 static RawObject* Spawn(NativeArguments* arguments, SpawnState* state) {
@@ skipping 99 matching lines @@
 
 DEFINE_NATIVE_ENTRY(isolate_getPortInternal, 0) {
   const Object& port = Object::Handle(ReceivePortCreate(isolate->main_port()));
   if (port.IsError()) {
     Exceptions::PropagateError(Error::Cast(port));
   }
   return port.raw();
 }
 
 }  // namespace dart