Fix issue 13942 - Dart_Error function invokes OS::VSNPrint with the "format" string containing data…

runtime/bin/vmservice_impl.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 "bin/vmservice_impl.h"
 
 #include "include/dart_api.h"
 
 #include "bin/builtin.h"
 #include "bin/dartutils.h"
@@ skipping 272 matching lines @@
 
 static bool IsVMServiceLibrary(const char* url) {
   return 0 == strcmp(kVMServiceLibraryName, url);
 }
 
 
 Dart_Handle VmService::LibraryTagHandler(Dart_LibraryTag tag,
                                          Dart_Handle library,
                                          Dart_Handle url) {
   if (!Dart_IsLibrary(library)) {
-    return Dart_Error("not a library");
+    return Dart_NewApiError("not a library");
   }
   if (!Dart_IsString(url)) {
-    return Dart_Error("url is not a string");
+    return Dart_NewApiError("url is not a string");
   }
   const char* url_string = NULL;
   Dart_Handle result = Dart_StringToCString(url, &url_string);
   if (Dart_IsError(result)) {
     return result;
   }
   Dart_Handle library_url = Dart_LibraryUrl(library);
   const char* library_url_string = NULL;
   result = Dart_StringToCString(library_url, &library_url_string);
   if (Dart_IsError(result)) {
@@ skipping 212 matching lines @@
     if (!strcmp(function_name, entry.name) &&
         (num_arguments == entry.num_arguments)) {
       return entry.function;
     }
   }
   return NULL;
 }
 
 }  // namespace bin
 }  // namespace dart