Fix for issue 21398 (only send "literal like" objects across isolates spawned using spawnURI

runtime/vm/json_stream.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 "platform/assert.h"
 
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
 #include "vm/json_stream.h"
 #include "vm/message.h"
@@ skipping 84 matching lines @@
   ASSERT(port != ILLEGAL_PORT);
   set_reply_port(ILLEGAL_PORT);  // Prevent double replies.
   int64_t process_delta_micros = 0;
   if (FLAG_trace_service) {
     process_delta_micros = OS::GetCurrentTimeMicros() - setup_time_micros_;
   }
   const String& reply = String::Handle(String::New(ToCString()));
   ASSERT(!reply.IsNull());
 
   uint8_t* data = NULL;
-  MessageWriter writer(&data, &allocator);
+  MessageWriter writer(&data, &allocator, false);
   writer.WriteMessage(reply);
   PortMap::PostMessage(new Message(port, data,
                                    writer.BytesWritten(),
                                    Message::kNormalPriority));
   if (FLAG_trace_service) {
     Isolate* isolate = Isolate::Current();
     ASSERT(isolate != NULL);
     const char* isolate_name = isolate->name();
     OS::Print("Isolate %s processed service request /%s",
               isolate_name, command_);
@@ skipping 391 matching lines @@
   intptr_t len2 = OS::VSNPrint(p, len+1, format, args);
   va_end(args);
   ASSERT(len == len2);
   stream_->buffer_.AddChar('"');
   stream_->AddEscapedUTF8String(p);
   stream_->buffer_.AddChar('"');
   free(p);
 }
 
 }  // namespace dart