Make VM service id handling JSON-RPC 2 compliant.

runtime/vm/json_stream.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_JSON_STREAM_H_
 #define VM_JSON_STREAM_H_
 
 #include "include/dart_api.h"  // for Dart_Port
 #include "platform/json.h"
 #include "vm/allocation.h"
@@ skipping 39 matching lines @@
 };
 
 
 class JSONStream : ValueObject {
  public:
   explicit JSONStream(intptr_t buf_size = 256);
   ~JSONStream();
 
   void Setup(Zone* zone,
              Dart_Port reply_port,
-             const String& seq,
+             const Instance& seq,
              const String& method,
              const Array& param_keys,
              const Array& param_values);
   void SetupError();
 
   void PrintError(intptr_t code, const char* details_format, ...);
 
   void PostReply();
 
   void set_id_zone(ServiceIdZone* id_zone) {
@@ skipping 22 matching lines @@
   }
 
   const char* LookupParam(const char* key) const;
 
   bool HasParam(const char* key) const;
 
   // Returns true if there is an param with key and value, false
   // otherwise.
   bool ParamIs(const char* key, const char* value) const;
 
-  const char* seq() const { return seq_; }
   const char* method() const { return method_; }
   const char** param_keys() const { return param_keys_; }
   const char** param_values() const { return param_values_; }
 
  private:
   void Clear();
 
   void OpenObject(const char* property_name = NULL);
   void CloseObject();
 
@@ skipping 50 matching lines @@
   void AddEscapedUTF8String(const char* s, intptr_t len);
 
   intptr_t nesting_level() const { return open_objects_; }
 
   intptr_t open_objects_;
   TextBuffer buffer_;
   // Default service id zone.
   RingServiceIdZone default_id_zone_;
   ServiceIdZone* id_zone_;
   Dart_Port reply_port_;
-  const char* seq_;
+  Instance& seq_;
   const char* method_;
   const char** param_keys_;
   const char** param_values_;
   intptr_t num_params_;
   int64_t setup_time_micros_;
 
   friend class JSONObject;
   friend class JSONArray;
 };
 
@@ skipping 138 matching lines @@
 
   friend class JSONObject;
 
   DISALLOW_ALLOCATION();
   DISALLOW_COPY_AND_ASSIGN(JSONArray);
 };
 
 }  // namespace dart
 
 #endif  // VM_JSON_STREAM_H_