- Remove stale code.

runtime/vm/isolate.cc

 // Copyright (c) 2013, 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/isolate.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/json.h"
 #include "vm/code_observers.h"
@@ skipping 1428 matching lines @@
 Dart_IsolateCreateCallback Isolate::create_callback_ = NULL;
 Dart_IsolateInterruptCallback Isolate::interrupt_callback_ = NULL;
 Dart_IsolateUnhandledExceptionCallback
     Isolate::unhandled_exception_callback_ = NULL;
 Dart_IsolateShutdownCallback Isolate::shutdown_callback_ = NULL;
 Dart_FileOpenCallback Isolate::file_open_callback_ = NULL;
 Dart_FileReadCallback Isolate::file_read_callback_ = NULL;
 Dart_FileWriteCallback Isolate::file_write_callback_ = NULL;
 Dart_FileCloseCallback Isolate::file_close_callback_ = NULL;
 Dart_EntropySource Isolate::entropy_source_callback_ = NULL;
-Dart_IsolateInterruptCallback Isolate::vmstats_callback_ = NULL;
 
 Monitor* Isolate::isolates_list_monitor_ = NULL;
 Isolate* Isolate::isolates_list_head_ = NULL;
 
 
 void Isolate::VisitObjectPointers(ObjectPointerVisitor* visitor,
                                   bool visit_prologue_weak_handles,
                                   bool validate_frames) {
   ASSERT(visitor != NULL);
 
@@ skipping 510 matching lines @@
                            serialized_message_, serialized_message_len_);
 }
 
 
 void IsolateSpawnState::Cleanup() {
   SwitchIsolateScope switch_scope(I);
   Dart::ShutdownIsolate();
 }
 
 }  // namespace dart