Reuse the top ApiLocalScope so that we do not allocate and free an ApiLocalScope

runtime/vm/zone.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/zone.h"
 
 #include "platform/assert.h"
 #include "platform/utils.h"
 #include "vm/flags.h"
+#include "vm/handles_impl.h"
 #include "vm/heap.h"
 #include "vm/isolate.h"
 #include "vm/os.h"
 
 namespace dart {
 
 DEFINE_DEBUG_FLAG(bool, trace_zones,
                   false, "Traces allocation sizes in the zone.");
 
 
@@ skipping 87 matching lines @@
   Segment::DeleteSegmentList(large_segments_);
 
   // Reset zone state.
 #ifdef DEBUG
   memset(initial_buffer_.pointer(), kZapDeletedByte, initial_buffer_.size());
 #endif
   position_ = initial_buffer_.start();
   limit_ = initial_buffer_.end();
   head_ = NULL;
   large_segments_ = NULL;
+  previous_ = NULL;
+  handles_.Reset();
 }
 
 
 intptr_t Zone::SizeInBytes() const {
   intptr_t size = 0;
   for (Segment* s = large_segments_; s != NULL; s = s->next()) {
     size += s->size();
   }
   if (head_ == NULL) {
     return size + (position_ - initial_buffer_.start());
@@ skipping 129 matching lines @@
   va_list args2;
   va_start(args2, format);
   OS::VSNPrint(buffer, (len + 1), format, args2);
   va_end(args2);
 
   return buffer;
 }
 
 
 }  // namespace dart