Fix a bug where breakpoints where not getting properly deleted.

runtime/vm/isolate.h

 // 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.
 
 #ifndef VM_ISOLATE_H_
 #define VM_ISOLATE_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/atomic.h"
@@ skipping 700 matching lines @@
   // being thread specific.
   uword stack_limit_;
   StoreBuffer* store_buffer_;
   Heap* heap_;
   uword user_tag_;
   RawUserTag* current_tag_;
   RawUserTag* default_tag_;
   RawCode* ic_miss_code_;
   ClassTable class_table_;
   bool single_step_;
+  bool skip_step_;  // skip the next single step.
 
   ThreadRegistry* thread_registry_;
   Dart_MessageNotifyCallback message_notify_callback_;
   char* name_;
   char* debugger_name_;
   int64_t start_time_;
   Dart_Port main_port_;
   Dart_Port origin_id_;  // Isolates created by spawnFunc have some origin id.
   uint64_t pause_capability_;
   uint64_t terminate_capability_;
@@ skipping 259 matching lines @@
   intptr_t* spawn_count_;
 
   Isolate::Flags isolate_flags_;
   bool paused_;
   bool errors_are_fatal_;
 };
 
 }  // namespace dart
 
 #endif  // VM_ISOLATE_H_