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

vm/pages.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 "vm/pages.h"
 
 #include "platform/assert.h"
 #include "vm/gc_marker.h"
 #include "vm/gc_sweeper.h"
 #include "vm/object.h"
@@ skipping 244 matching lines @@
   }
   return Object::null();
 }
 
 
 void PageSpace::MarkSweep(bool invoke_api_callbacks) {
   // MarkSweep is not reentrant. Make sure that is the case.
   ASSERT(!sweeping_);
   sweeping_ = true;
   Isolate* isolate = Isolate::Current();
-  NoHandleScope no_handles(isolate);
+  NOHANDLESCOPE(isolate);
 
   if (FLAG_verify_before_gc) {
     OS::PrintErr("Verifying before MarkSweep... ");
     heap_->Verify();
     OS::PrintErr(" done.\n");
   }
 
   Timer timer(FLAG_verbose_gc, "MarkSweep");
   timer.Start();
 
@@ skipping 51 matching lines @@
     OS::PrintErr(" done.\n");
   }
 
   count_++;
   // Done, reset the marker.
   ASSERT(sweeping_);
   sweeping_ = false;
 }
 
 }  // namespace dart