Add fast paths for Smi values in the dart embedding api.

vm/scavenger.cc

 // Copyright (c) 2011, 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 "vm/scavenger.h"
 
 #include "vm/dart.h"
 #include "vm/dart_api_state.h"
 #include "vm/isolate.h"
 #include "vm/object.h"
@@ skipping 337 matching lines @@
   // the API callbacks should be invoked.
   Scavenge(false);
 }
 
 
 void Scavenger::Scavenge(bool invoke_api_callbacks) {
   // Scavenging is not reentrant. Make sure that is the case.
   ASSERT(!scavenging_);
   scavenging_ = true;
   Isolate* isolate = Isolate::Current();
-  NoHandleScope no_handles(isolate);
+  NOHANDLESCOPE(isolate);
 
   if (FLAG_verify_before_gc) {
     OS::PrintErr("Verifying before Scavenge... ");
     heap_->Verify();
     OS::PrintErr(" done.\n");
   }
 
   Timer timer(FLAG_verbose_gc, "Scavenge");
   timer.Start();
   // Setup the visitor and run a scavenge.
@@ skipping 16 matching lines @@
     OS::PrintErr(" done.\n");
   }
 
   count_++;
   // Done scavenging. Reset the marker.
   ASSERT(scavenging_);
   scavenging_ = false;
 }
 
 }  // namespace dart