Start 'fuzzing' of dart:io APIs and fix first issue found.

runtime/vm/dart_api_message.h

 // Copyright (c) 2012, 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_DART_API_MESSAGE_H_
 #define VM_DART_API_MESSAGE_H_
 
 #include "vm/dart_api_state.h"
 #include "vm/snapshot.h"
 
@@ skipping 19 matching lines @@
   ApiMessageReader(const uint8_t* buffer, intptr_t length, ReAlloc alloc);
   ~ApiMessageReader() { }
 
   Dart_CObject* ReadMessage();
 
  private:
   // Allocates a Dart_CObject object.
   Dart_CObject* AllocateDartCObject();
   // Allocates a Dart_CObject object with the specified type.
   Dart_CObject* AllocateDartCObject(Dart_CObject::Type type);
+  // Allocates a Dart_CObject object representing an unsupported
+  // object in the API message.
+  Dart_CObject* AllocateDartCObjectUnsupported();
   // Allocates a Dart_CObject object for the null object.
   Dart_CObject* AllocateDartCObjectNull();
   // Allocates a Dart_CObject object for a boolean object.
   Dart_CObject* AllocateDartCObjectBool(bool value);
   // Allocates a Dart_CObject object for for a 32-bit integer.
   Dart_CObject* AllocateDartCObjectInt32(int32_t value);
   // Allocates a Dart_CObject object for for a 64-bit integer.
   Dart_CObject* AllocateDartCObjectInt64(int64_t value);
   // Allocates a Dart_CObject object for bigint data.
   Dart_CObject* AllocateDartCObjectBigint(intptr_t length);
@@ skipping 70 matching lines @@
   void WriteCObject(Dart_CObject* object);
 
   intptr_t object_id_;
 
   DISALLOW_COPY_AND_ASSIGN(ApiMessageWriter);
 };
 
 }  // namespace dart
 
 #endif  // VM_DART_API_MESSAGE_H_